diff --git a/cmd-bind-key.c b/cmd-bind-key.c
index fda39efc..1867e814 100644
--- a/cmd-bind-key.c
+++ b/cmd-bind-key.c
@@ -29,7 +29,8 @@
 
 enum cmd_retval	 cmd_bind_key_exec(struct cmd *, struct cmd_q *);
 
-enum cmd_retval	 cmd_bind_key_mode_table(struct cmd *, struct cmd_q *, int);
+enum cmd_retval	 cmd_bind_key_mode_table(struct cmd *, struct cmd_q *,
+		     key_code);
 
 const struct cmd_entry cmd_bind_key_entry = {
 	"bind-key", "bind",
@@ -45,7 +46,7 @@ cmd_bind_key_exec(struct cmd *self, struct cmd_q *cmdq)
 	struct args	*args = self->args;
 	char		*cause;
 	struct cmd_list	*cmdlist;
-	int		 key;
+	key_code	 key;
 	const char	*tablename;
 
 	if (args_has(args, 't')) {
@@ -89,7 +90,7 @@ cmd_bind_key_exec(struct cmd *self, struct cmd_q *cmdq)
 }
 
 enum cmd_retval
-cmd_bind_key_mode_table(struct cmd *self, struct cmd_q *cmdq, int key)
+cmd_bind_key_mode_table(struct cmd *self, struct cmd_q *cmdq, key_code key)
 {
 	struct args			*args = self->args;
 	const char			*tablename;
diff --git a/cmd-list-keys.c b/cmd-list-keys.c
index d26486bd..c76f9f47 100644
--- a/cmd-list-keys.c
+++ b/cmd-list-keys.c
@@ -57,6 +57,7 @@ cmd_list_keys_exec(struct cmd *self, struct cmd_q *cmdq)
 	char			 tmp[BUFSIZ];
 	size_t			 used;
 	int			 repeat, width, tablewidth, keywidth;
+	u_int			 i;
 
 	if (self->entry == &cmd_list_commands_entry)
 		return (cmd_list_keys_commands(self, cmdq));
@@ -83,8 +84,8 @@ cmd_list_keys_exec(struct cmd *self, struct cmd_q *cmdq)
 
 			width = strlen(table->name);
 			if (width > tablewidth)
-				tablewidth =width;
-			width = strlen(key);
+				tablewidth = width;
+			width = utf8_cstrwidth(key);
 			if (width > keywidth)
 				keywidth = width;
 		}
@@ -102,8 +103,12 @@ cmd_list_keys_exec(struct cmd *self, struct cmd_q *cmdq)
 				r = "-r ";
 			else
 				r = "   ";
-			used = xsnprintf(tmp, sizeof tmp, "%s-T %-*s %-*s ", r,
-			    (int)tablewidth, table->name, (int)keywidth, key);
+			used = xsnprintf(tmp, sizeof tmp, "%s-T %-*s %s", r,
+			    (int)tablewidth, table->name, key);
+			for (i = 0; i < keywidth - utf8_cstrwidth(key); i++) {
+				if (strlcat(tmp, " ", sizeof tmp) < sizeof tmp)
+					used++;
+			}
 			if (used < sizeof tmp) {
 				cmd_list_print(bd->cmdlist, tmp + used,
 				    (sizeof tmp) - used);
diff --git a/cmd-send-keys.c b/cmd-send-keys.c
index dd796d60..73a308ae 100644
--- a/cmd-send-keys.c
+++ b/cmd-send-keys.c
@@ -53,7 +53,8 @@ cmd_send_keys_exec(struct cmd *self, struct cmd_q *cmdq)
 	struct window_pane	*wp;
 	struct session		*s;
 	const u_char		*str;
-	int			 i, key;
+	int			 i;
+	key_code		 key;
 
 	if (args_has(args, 'M')) {
 		wp = cmd_mouse_pane(m, &s, NULL);
diff --git a/cmd-set-option.c b/cmd-set-option.c
index 6762e6ad..c5a77b45 100644
--- a/cmd-set-option.c
+++ b/cmd-set-option.c
@@ -394,7 +394,7 @@ cmd_set_option_key(unused struct cmd *self, struct cmd_q *cmdq,
     const struct options_table_entry *oe, struct options *oo,
     const char *value)
 {
-	int	key;
+	key_code	key;
 
 	if ((key = key_string_lookup_string(value)) == KEYC_NONE) {
 		cmdq_error(cmdq, "bad key: %s", value);
diff --git a/cmd-unbind-key.c b/cmd-unbind-key.c
index 493f6dde..cec538c0 100644
--- a/cmd-unbind-key.c
+++ b/cmd-unbind-key.c
@@ -26,8 +26,9 @@
  * Unbind key from command.
  */
 
-enum cmd_retval	 cmd_unbind_key_exec(struct cmd *, struct cmd_q *);
-enum cmd_retval	 cmd_unbind_key_mode_table(struct cmd *, struct cmd_q *, int);
+enum cmd_retval	cmd_unbind_key_exec(struct cmd *, struct cmd_q *);
+enum cmd_retval	cmd_unbind_key_mode_table(struct cmd *, struct cmd_q *,
+		    key_code);
 
 const struct cmd_entry cmd_unbind_key_entry = {
 	"unbind-key", "unbind",
@@ -41,7 +42,7 @@ enum cmd_retval
 cmd_unbind_key_exec(struct cmd *self, struct cmd_q *cmdq)
 {
 	struct args	*args = self->args;
-	int		 key;
+	key_code	 key;
 	const char	*tablename;
 
 	if (!args_has(args, 'a')) {
@@ -95,7 +96,7 @@ cmd_unbind_key_exec(struct cmd *self, struct cmd_q *cmdq)
 }
 
 enum cmd_retval
-cmd_unbind_key_mode_table(struct cmd *self, struct cmd_q *cmdq, int key)
+cmd_unbind_key_mode_table(struct cmd *self, struct cmd_q *cmdq, key_code key)
 {
 	struct args			*args = self->args;
 	const char			*tablename;
diff --git a/input-keys.c b/input-keys.c
index 579c0f39..a761a088 100644
--- a/input-keys.c
+++ b/input-keys.c
@@ -34,7 +34,7 @@
 void	 input_key_mouse(struct window_pane *, struct mouse_event *);
 
 struct input_key_ent {
-	int		 key;
+	key_code	 key;
 	const char	*data;
 
 	int		 flags;
@@ -137,15 +137,16 @@ const struct input_key_ent input_keys[] = {
 
 /* Translate a key code into an output key sequence. */
 void
-input_key(struct window_pane *wp, int key, struct mouse_event *m)
+input_key(struct window_pane *wp, key_code key, struct mouse_event *m)
 {
-	const struct input_key_ent     *ike;
-	u_int				i;
-	size_t				dlen;
-	char			       *out;
-	u_char				ch;
+	const struct input_key_ent	*ike;
+	u_int				 i;
+	size_t				 dlen;
+	char				*out;
+	key_code			 justkey;
+	struct utf8_data		 utf8data;
 
-	log_debug("writing key 0x%x (%s) to %%%u", key,
+	log_debug("writing key 0x%llx (%s) to %%%u", key,
 	    key_string_lookup_key(key), wp->id);
 
 	/* If this is a mouse key, pass off to mouse function. */
@@ -157,13 +158,22 @@ input_key(struct window_pane *wp, int key, struct mouse_event *m)
 
 	/*
 	 * If this is a normal 7-bit key, just send it, with a leading escape
-	 * if necessary.
+	 * if necessary. If it is a UTF-8 key, split it and send it.
 	 */
-	if (key != KEYC_NONE && (key & ~KEYC_ESCAPE) < 0x100) {
+	justkey = (key & ~KEYC_ESCAPE);
+	if (key != KEYC_NONE && justkey < 0x7f) {
 		if (key & KEYC_ESCAPE)
 			bufferevent_write(wp->event, "\033", 1);
-		ch = key & ~KEYC_ESCAPE;
-		bufferevent_write(wp->event, &ch, 1);
+		utf8data.data[0] = justkey;
+		bufferevent_write(wp->event, &utf8data.data[0], 1);
+		return;
+	}
+	if (key != KEYC_NONE && justkey > 0x7f && justkey < KEYC_BASE) {
+		if (utf8_split(justkey, &utf8data) != 0)
+			return;
+		if (key & KEYC_ESCAPE)
+			bufferevent_write(wp->event, "\033", 1);
+		bufferevent_write(wp->event, utf8data.data, utf8data.size);
 		return;
 	}
 
@@ -196,11 +206,11 @@ input_key(struct window_pane *wp, int key, struct mouse_event *m)
 			break;
 	}
 	if (i == nitems(input_keys)) {
-		log_debug("key 0x%x missing", key);
+		log_debug("key 0x%llx missing", key);
 		return;
 	}
 	dlen = strlen(ike->data);
-	log_debug("found key 0x%x: \"%s\"", key, ike->data);
+	log_debug("found key 0x%llx: \"%s\"", key, ike->data);
 
 	/* Prefix a \033 for escape. */
 	if (key & KEYC_ESCAPE)
diff --git a/key-bindings.c b/key-bindings.c
index 83b94ac1..47a7d867 100644
--- a/key-bindings.c
+++ b/key-bindings.c
@@ -37,7 +37,11 @@ key_table_cmp(struct key_table *e1, struct key_table *e2)
 int
 key_bindings_cmp(struct key_binding *bd1, struct key_binding *bd2)
 {
-	return (bd1->key - bd2->key);
+	if (bd1->key < bd2->key)
+		return (-1);
+	if (bd1->key > bd2->key)
+		return (1);
+	return (0);
 }
 
 struct key_table *
@@ -80,7 +84,7 @@ key_bindings_unref_table(struct key_table *table)
 }
 
 void
-key_bindings_add(const char *name, int key, int can_repeat,
+key_bindings_add(const char *name, key_code key, int can_repeat,
     struct cmd_list *cmdlist)
 {
 	struct key_table	*table;
@@ -105,7 +109,7 @@ key_bindings_add(const char *name, int key, int can_repeat,
 }
 
 void
-key_bindings_remove(const char *name, int key)
+key_bindings_remove(const char *name, key_code key)
 {
 	struct key_table	*table;
 	struct key_binding	 bd_find, *bd;
diff --git a/key-string.c b/key-string.c
index 88cd2a32..4285e129 100644
--- a/key-string.c
+++ b/key-string.c
@@ -22,12 +22,12 @@
 
 #include "tmux.h"
 
-int	key_string_search_table(const char *);
-int	key_string_get_modifiers(const char **);
+key_code	key_string_search_table(const char *);
+key_code	key_string_get_modifiers(const char **);
 
 const struct {
 	const char     *string;
-	int	 	key;
+	key_code	key;
 } key_string_table[] = {
 	/* Function keys. */
 	{ "F1",		KEYC_F1 },
@@ -98,7 +98,7 @@ const struct {
 };
 
 /* Find key string in table. */
-int
+key_code
 key_string_search_table(const char *string)
 {
 	u_int	i;
@@ -111,10 +111,10 @@ key_string_search_table(const char *string)
 }
 
 /* Find modifiers. */
-int
+key_code
 key_string_get_modifiers(const char **string)
 {
-	int	modifiers;
+	key_code	modifiers;
 
 	modifiers = 0;
 	while (((*string)[0] != '\0') && (*string)[1] == '-') {
@@ -138,13 +138,16 @@ key_string_get_modifiers(const char **string)
 }
 
 /* Lookup a string and convert to a key value. */
-int
+key_code
 key_string_lookup_string(const char *string)
 {
 	static const char	*other = "!#()+,-.0123456789:;<=>?'\r\t";
-	int			 key, modifiers;
+	key_code		 key;
 	u_short			 u;
 	int			 size;
+	key_code		 modifiers;
+	struct utf8_data	 utf8data;
+	u_int			 i;
 
 	/* Is this a hexadecimal value? */
 	if (string[0] == '0' && string[1] == 'x') {
@@ -164,11 +167,21 @@ key_string_lookup_string(const char *string)
 		return (KEYC_NONE);
 
 	/* Is this a standard ASCII key? */
-	if (string[1] == '\0') {
-		key = (u_char) string[0];
-		if (key < 32 || key == 127 || key > 255)
+	if (string[1] == '\0' && (u_char)string[0] <= 127) {
+		key = (u_char)string[0];
+		if (key < 32 || key == 127)
 			return (KEYC_NONE);
 	} else {
+		/* Try as a UTF-8 key. */
+		if (utf8_open(&utf8data, (u_char)*string)) {
+			if (strlen(string) != utf8data.size)
+				return (KEYC_NONE);
+			for (i = 1; i < utf8data.size; i++)
+				utf8_append(&utf8data, (u_char)string[i]);
+			key = utf8_combine(&utf8data);
+			return (key | modifiers);
+		}
+
 		/* Otherwise look the key up in the table. */
 		key = key_string_search_table(string);
 		if (key == KEYC_NONE)
@@ -195,11 +208,12 @@ key_string_lookup_string(const char *string)
 
 /* Convert a key code into string format, with prefix if necessary. */
 const char *
-key_string_lookup_key(int key)
+key_string_lookup_key(key_code key)
 {
-	static char	out[24];
-	char		tmp[8];
-	u_int		i;
+	static char		out[24];
+	char			tmp[8];
+	u_int			i;
+	struct utf8_data	utf8data;
 
 	*out = '\0';
 
@@ -237,23 +251,32 @@ key_string_lookup_key(int key)
 		return (out);
 	}
 
+	/* Is this a UTF-8 key? */
+	if (key > 127 && key < KEYC_BASE) {
+		if (utf8_split(key, &utf8data) == 0) {
+			memcpy(out, utf8data.data, utf8data.size);
+			out[utf8data.size] = '\0';
+			return (out);
+		}
+	}
+
 	/* Invalid keys are errors. */
 	if (key == 127 || key > 255) {
-		snprintf(out, sizeof out, "<INVALID#%04x>", key);
+		snprintf(out, sizeof out, "<INVALID#%llx>", key);
 		return (out);
 	}
 
 	/* Check for standard or control key. */
-	if (key >= 0 && key <= 32) {
+	if (key <= 32) {
 		if (key == 0 || key > 26)
-			xsnprintf(tmp, sizeof tmp, "C-%c", 64 + key);
+			xsnprintf(tmp, sizeof tmp, "C-%c", (int)(64 + key));
 		else
-			xsnprintf(tmp, sizeof tmp, "C-%c", 96 + key);
+			xsnprintf(tmp, sizeof tmp, "C-%c", (int)(96 + key));
 	} else if (key >= 32 && key <= 126) {
 		tmp[0] = key;
 		tmp[1] = '\0';
 	} else if (key >= 128)
-		xsnprintf(tmp, sizeof tmp, "\\%o", key);
+		xsnprintf(tmp, sizeof tmp, "\\%llo", key);
 
 	strlcat(out, tmp, sizeof out);
 	return (out);
diff --git a/mode-key.c b/mode-key.c
index 5ed45bd8..a47cda0b 100644
--- a/mode-key.c
+++ b/mode-key.c
@@ -40,7 +40,7 @@
 
 /* Entry in the default mode key tables. */
 struct mode_key_entry {
-	int			key;
+	key_code		key;
 
 	/*
 	 * Editing mode for vi: 0 is edit mode, keys not in the table are
@@ -523,9 +523,15 @@ RB_GENERATE(mode_key_tree, mode_key_binding, entry, mode_key_cmp);
 int
 mode_key_cmp(struct mode_key_binding *mbind1, struct mode_key_binding *mbind2)
 {
-	if (mbind1->mode != mbind2->mode)
-		return (mbind1->mode - mbind2->mode);
-	return (mbind1->key - mbind2->key);
+	if (mbind1->mode < mbind2->mode)
+		return (-1);
+	if (mbind1->mode > mbind2->mode)
+		return (1);
+	if (mbind1->key < mbind2->key)
+		return (-1);
+	if (mbind1->key > mbind2->key)
+		return (1);
+	return (0);
 }
 
 const char *
@@ -588,7 +594,7 @@ mode_key_init(struct mode_key_data *mdata, struct mode_key_tree *mtree)
 }
 
 enum mode_key_cmd
-mode_key_lookup(struct mode_key_data *mdata, int key, const char **arg)
+mode_key_lookup(struct mode_key_data *mdata, key_code key, const char **arg)
 {
 	struct mode_key_binding	*mbind, mtmp;
 
diff --git a/server-client.c b/server-client.c
index 521f2737..fedc93bd 100644
--- a/server-client.c
+++ b/server-client.c
@@ -32,22 +32,22 @@
 
 #include "tmux.h"
 
-void	server_client_key_table(struct client *, const char *);
-void	server_client_free(int, short, void *);
-void	server_client_check_focus(struct window_pane *);
-void	server_client_check_resize(struct window_pane *);
-int	server_client_check_mouse(struct client *);
-void	server_client_repeat_timer(int, short, void *);
-void	server_client_check_exit(struct client *);
-void	server_client_check_redraw(struct client *);
-void	server_client_set_title(struct client *);
-void	server_client_reset_state(struct client *);
-int	server_client_assume_paste(struct session *);
+void		server_client_key_table(struct client *, const char *);
+void		server_client_free(int, short, void *);
+void		server_client_check_focus(struct window_pane *);
+void		server_client_check_resize(struct window_pane *);
+key_code	server_client_check_mouse(struct client *);
+void		server_client_repeat_timer(int, short, void *);
+void		server_client_check_exit(struct client *);
+void		server_client_check_redraw(struct client *);
+void		server_client_set_title(struct client *);
+void		server_client_reset_state(struct client *);
+int		server_client_assume_paste(struct session *);
 
-void	server_client_dispatch(struct imsg *, void *);
-void	server_client_dispatch_command(struct client *, struct imsg *);
-void	server_client_dispatch_identify(struct client *, struct imsg *);
-void	server_client_dispatch_shell(struct client *);
+void		server_client_dispatch(struct imsg *, void *);
+void		server_client_dispatch_command(struct client *, struct imsg *);
+void		server_client_dispatch_identify(struct client *, struct imsg *);
+void		server_client_dispatch_shell(struct client *);
 
 /* Check if this client is inside this server. */
 int
@@ -257,7 +257,7 @@ server_client_free(unused int fd, unused short events, void *arg)
 }
 
 /* Check for mouse keys. */
-int
+key_code
 server_client_check_mouse(struct client *c)
 {
 	struct session				*s = c->session;
@@ -267,7 +267,7 @@ server_client_check_mouse(struct client *c)
 	enum { NOTYPE, DOWN, UP, DRAG, WHEEL }	 type = NOTYPE;
 	enum { NOWHERE, PANE, STATUS, BORDER }	 where = NOWHERE;
 	u_int					 x, y, b;
-	int					 key;
+	key_code				 key;
 
 	log_debug("mouse %02x at %u,%u (last %u,%u) (%d)", m->b, m->x, m->y,
 	    m->lx, m->ly, c->tty.mouse_drag_flag);
@@ -501,7 +501,7 @@ server_client_assume_paste(struct session *s)
 
 /* Handle data key input from client. */
 void
-server_client_handle_key(struct client *c, int key)
+server_client_handle_key(struct client *c, key_code key)
 {
 	struct mouse_event	*m = &c->tty.mouse;
 	struct session		*s = c->session;
@@ -635,8 +635,8 @@ retry:
 	 * No match, but in the root table. Prefix switches to the prefix table
 	 * and everything else is passed through.
 	 */
-	if (key == options_get_number(s->options, "prefix") ||
-	    key == options_get_number(s->options, "prefix2")) {
+	if (key == (key_code)options_get_number(s->options, "prefix") ||
+	    key == (key_code)options_get_number(s->options, "prefix2")) {
 		server_client_key_table(c, "prefix");
 		server_status_client(c);
 		return;
diff --git a/status.c b/status.c
index a2f46b95..df80d2b8 100644
--- a/status.c
+++ b/status.c
@@ -812,7 +812,7 @@ status_prompt_redraw(struct client *c)
 
 /* Handle keys in prompt. */
 void
-status_prompt_key(struct client *c, int key)
+status_prompt_key(struct client *c, key_code key)
 {
 	struct session		*sess = c->session;
 	struct options		*oo = sess->options;
@@ -1116,7 +1116,7 @@ status_prompt_key(struct client *c, int key)
 			status_prompt_clear(c);
 		break;
 	case MODEKEY_OTHER:
-		if ((key & 0xff00) != 0 || key < 32 || key == 127)
+		if (key <= 0x1f || key >= 0x7f)
 			break;
 		c->prompt_buffer = xrealloc(c->prompt_buffer, size + 2);
 
diff --git a/tmux.h b/tmux.h
index 25b51350..51ceefd8 100644
--- a/tmux.h
+++ b/tmux.h
@@ -95,13 +95,13 @@ struct tmuxproc;
 #define BELL_OTHER 3
 
 /* Special key codes. */
-#define KEYC_NONE 0xfff
-#define KEYC_BASE 0x1000
+#define KEYC_NONE 0xffff00000000ULL
+#define KEYC_BASE 0x100000000000ULL
 
 /* Key modifier bits. */
-#define KEYC_ESCAPE 0x2000
-#define KEYC_CTRL 0x4000
-#define KEYC_SHIFT 0x8000
+#define KEYC_ESCAPE 0x200000000000ULL
+#define KEYC_CTRL   0x400000000000ULL
+#define KEYC_SHIFT  0x800000000000ULL
 
 /* Mask to obtain key w/o modifiers. */
 #define KEYC_MASK_MOD (KEYC_ESCAPE|KEYC_CTRL|KEYC_SHIFT)
@@ -121,8 +121,14 @@ struct tmuxproc;
 	{ #s "Status", KEYC_ ## name ## _STATUS },	\
 	{ #s "Border", KEYC_ ## name ## _BORDER }
 
+/*
+ * A single key. This can be ASCII or Unicode or one of the keys starting at
+ * KEYC_BASE.
+ */
+typedef uint64_t key_code;
+
 /* Special key codes. */
-enum key_code {
+enum {
 	/* Focus events. */
 	KEYC_FOCUS_IN = KEYC_BASE,
 	KEYC_FOCUS_OUT,
@@ -570,7 +576,7 @@ struct mode_key_data {
 
 /* Binding between a key and a command. */
 struct mode_key_binding {
-	int				 key;
+	key_code			 key;
 
 	int				 mode;
 	enum mode_key_cmd		 cmd;
@@ -776,7 +782,7 @@ struct window_mode {
 	void	(*free)(struct window_pane *);
 	void	(*resize)(struct window_pane *, u_int, u_int);
 	void	(*key)(struct window_pane *, struct client *, struct session *,
-		    int, struct mouse_event *);
+		    key_code, struct mouse_event *);
 };
 
 /* Structures for choose mode. */
@@ -1030,31 +1036,31 @@ RB_HEAD(sessions, session);
 
 /* Mouse input. */
 struct mouse_event {
-	int	valid;
+	int		valid;
 
-	int	key;
-	int	statusat;
+	key_code	key;
+	int		statusat;
 
-	u_int	x;
-	u_int	y;
-	u_int	b;
+	u_int		x;
+	u_int		y;
+	u_int		b;
 
-	u_int	lx;
-	u_int	ly;
-	u_int	lb;
+	u_int		lx;
+	u_int		ly;
+	u_int		lb;
 
-	int	s;
-	int	w;
-	int	wp;
+	int		s;
+	int		w;
+	int		wp;
 
-	u_int	sgr_type;
-	u_int	sgr_b;
+	u_int		sgr_type;
+	u_int		sgr_b;
 };
 
 /* TTY information. */
 struct tty_key {
 	char		 ch;
-	int		 key;
+	key_code	 key;
 
 	struct tty_key	*left;
 	struct tty_key	*right;
@@ -1340,7 +1346,7 @@ struct cmd_entry {
 
 /* Key binding and key table. */
 struct key_binding {
-	int			 key;
+	key_code		 key;
 	struct cmd_list		*cmdlist;
 	int			 can_repeat;
 
@@ -1488,7 +1494,8 @@ enum mode_key_cmd mode_key_fromstring(const struct mode_key_cmdstr *,
 const struct mode_key_table *mode_key_findtable(const char *);
 void	mode_key_init_trees(void);
 void	mode_key_init(struct mode_key_data *, struct mode_key_tree *);
-enum mode_key_cmd mode_key_lookup(struct mode_key_data *, int, const char **);
+enum mode_key_cmd mode_key_lookup(struct mode_key_data *, key_code,
+	    const char **);
 
 /* notify.c */
 void	notify_enable(void);
@@ -1632,9 +1639,9 @@ const char	*tty_term_describe(struct tty_term *, enum tty_code_code);
 const char	*tty_acs_get(struct tty *, u_char);
 
 /* tty-keys.c */
-void	tty_keys_build(struct tty *);
-void	tty_keys_free(struct tty *);
-int	tty_keys_next(struct tty *);
+void		tty_keys_build(struct tty *);
+void		tty_keys_free(struct tty *);
+key_code	tty_keys_next(struct tty *);
 
 /* arguments.c */
 int		 args_cmp(struct args_entry *, struct args_entry *);
@@ -1720,16 +1727,16 @@ int	 key_table_cmp(struct key_table *, struct key_table *);
 int	 key_bindings_cmp(struct key_binding *, struct key_binding *);
 struct	 key_table *key_bindings_get_table(const char *, int);
 void	 key_bindings_unref_table(struct key_table *);
-void	 key_bindings_add(const char *, int, int, struct cmd_list *);
-void	 key_bindings_remove(const char *, int);
+void	 key_bindings_add(const char *, key_code, int, struct cmd_list *);
+void	 key_bindings_remove(const char *, key_code);
 void	 key_bindings_remove_table(const char *);
 void	 key_bindings_init(void);
 void	 key_bindings_dispatch(struct key_binding *, struct client *,
 	     struct mouse_event *);
 
 /* key-string.c */
-int	 key_string_lookup_string(const char *);
-const char *key_string_lookup_key(int);
+key_code	 key_string_lookup_string(const char *);
+const char	*key_string_lookup_key(key_code);
 
 /* alerts.c */
 void	alerts_reset_all(void);
@@ -1753,7 +1760,7 @@ void	 server_add_accept(int);
 
 /* server-client.c */
 int	 server_client_check_nested(struct client *);
-void	 server_client_handle_key(struct client *, int);
+void	 server_client_handle_key(struct client *, key_code);
 void	 server_client_create(int);
 int	 server_client_open(struct client *, char **);
 void	 server_client_unref(struct client *);
@@ -1803,7 +1810,7 @@ void	 status_prompt_set(struct client *, const char *, const char *,
 	     int (*)(void *, const char *), void (*)(void *), void *, int);
 void	 status_prompt_clear(struct client *);
 int	 status_prompt_redraw(struct client *);
-void	 status_prompt_key(struct client *, int);
+void	 status_prompt_key(struct client *, key_code);
 void	 status_prompt_update(struct client *, const char *, const char *);
 void	 status_prompt_load_history(void);
 void	 status_prompt_save_history(void);
@@ -1819,11 +1826,11 @@ struct evbuffer *input_pending(struct window_pane *);
 void	 input_parse(struct window_pane *);
 
 /* input-key.c */
-void	 input_key(struct window_pane *, int, struct mouse_event *);
+void	 input_key(struct window_pane *, key_code, struct mouse_event *);
 
 /* xterm-keys.c */
-char	*xterm_keys_lookup(int);
-int	 xterm_keys_find(const char *, size_t, size_t *, int *);
+char	*xterm_keys_lookup(key_code);
+int	 xterm_keys_find(const char *, size_t, size_t *, key_code *);
 
 /* colour.c */
 int	 colour_find_rgb(u_char, u_char, u_char);
@@ -2020,7 +2027,7 @@ int		 window_pane_set_mode(
 		     struct window_pane *, const struct window_mode *);
 void		 window_pane_reset_mode(struct window_pane *);
 void		 window_pane_key(struct window_pane *, struct client *,
-		     struct session *, int, struct mouse_event *);
+		     struct session *, key_code, struct mouse_event *);
 int		 window_pane_visible(struct window_pane *);
 char		*window_pane_search(
 		     struct window_pane *, const char *, u_int *);
@@ -2179,6 +2186,7 @@ void		 utf8_set(struct utf8_data *, u_char);
 int		 utf8_open(struct utf8_data *, u_char);
 int		 utf8_append(struct utf8_data *, u_char);
 u_int		 utf8_combine(const struct utf8_data *);
+int		 utf8_split(u_int, struct utf8_data *);
 u_int		 utf8_split2(u_int, u_char *);
 int		 utf8_strvis(char *, const char *, size_t, int);
 struct utf8_data *utf8_fromcstr(const char *);
diff --git a/tty-keys.c b/tty-keys.c
index 309e8c04..31adf0f0 100644
--- a/tty-keys.c
+++ b/tty-keys.c
@@ -33,11 +33,11 @@
  * into a ternary tree.
  */
 
-void		tty_keys_add1(struct tty_key **, const char *, int);
-void		tty_keys_add(struct tty *, const char *, int);
+void		tty_keys_add1(struct tty_key **, const char *, key_code);
+void		tty_keys_add(struct tty *, const char *, key_code);
 void		tty_keys_free1(struct tty_key *);
-struct tty_key *tty_keys_find1(
-		    struct tty_key *, const char *, size_t, size_t *);
+struct tty_key *tty_keys_find1(struct tty_key *, const char *, size_t,
+		    size_t *);
 struct tty_key *tty_keys_find(struct tty *, const char *, size_t, size_t *);
 void		tty_keys_callback(int, short, void *);
 int		tty_keys_mouse(struct tty *, const char *, size_t, size_t *);
@@ -45,7 +45,7 @@ int		tty_keys_mouse(struct tty *, const char *, size_t, size_t *);
 /* Default raw keys. */
 struct tty_default_key_raw {
 	const char	       *string;
-	int	 	 	key;
+	key_code	 	key;
 };
 const struct tty_default_key_raw tty_default_raw_keys[] = {
 	/*
@@ -165,7 +165,7 @@ const struct tty_default_key_raw tty_default_raw_keys[] = {
 /* Default terminfo(5) keys. */
 struct tty_default_key_code {
 	enum tty_code_code	code;
-	int	 	 	key;
+	key_code	 	key;
 };
 const struct tty_default_key_code tty_default_code_keys[] = {
 	/* Function keys. */
@@ -317,7 +317,7 @@ const struct tty_default_key_code tty_default_code_keys[] = {
 
 /* Add key to tree. */
 void
-tty_keys_add(struct tty *tty, const char *s, int key)
+tty_keys_add(struct tty *tty, const char *s, key_code key)
 {
 	struct tty_key	*tk;
 	size_t		 size;
@@ -325,17 +325,17 @@ tty_keys_add(struct tty *tty, const char *s, int key)
 
 	keystr = key_string_lookup_key(key);
 	if ((tk = tty_keys_find(tty, s, strlen(s), &size)) == NULL) {
-		log_debug("new key %s: 0x%x (%s)", s, key, keystr);
+		log_debug("new key %s: 0x%llx (%s)", s, key, keystr);
 		tty_keys_add1(&tty->key_tree, s, key);
 	} else {
-		log_debug("replacing key %s: 0x%x (%s)", s, key, keystr);
+		log_debug("replacing key %s: 0x%llx (%s)", s, key, keystr);
 		tk->key = key;
 	}
 }
 
 /* Add next node to the tree. */
 void
-tty_keys_add1(struct tty_key **tkp, const char *s, int key)
+tty_keys_add1(struct tty_key **tkp, const char *s, key_code key)
 {
 	struct tty_key	*tk;
 
@@ -464,15 +464,18 @@ tty_keys_find1(struct tty_key *tk, const char *buf, size_t len, size_t *size)
  * Process at least one key in the buffer and invoke tty->key_callback. Return
  * 0 if there are no further keys, or 1 if there could be more in the buffer.
  */
-int
+key_code
 tty_keys_next(struct tty *tty)
 {
-	struct tty_key	*tk;
-	struct timeval	 tv;
-	const char	*buf;
-	size_t		 len, size;
-	cc_t		 bspace;
-	int		 key, delay, expired = 0;
+	struct tty_key		*tk;
+	struct timeval		 tv;
+	const char		*buf;
+	size_t			 len, size;
+	cc_t			 bspace;
+	int			 delay, expired = 0;
+	key_code		 key;
+	struct utf8_data	 utf8data;
+	u_int			 i;
 
 	/* Get key buffer. */
 	buf = EVBUFFER_DATA(tty->event->input);
@@ -535,8 +538,23 @@ first_key:
 		}
 	}
 
+	/* Is this valid UTF-8? */
+	if (utf8_open(&utf8data, (u_char)*buf)) {
+		size = utf8data.size;
+		if (len < size) {
+			if (expired)
+				goto discard_key;
+			goto partial_key;
+		}
+		for (i = 1; i < size; i++)
+			utf8_append(&utf8data, (u_char)buf[i]);
+		key = utf8_combine(&utf8data);
+		log_debug("UTF-8 key %.*s %#llx", (int)size, buf, key);
+		goto complete_key;
+	}
+
 	/* No key found, take first. */
-	key = (u_char) *buf;
+	key = (u_char)*buf;
 	size = 1;
 
 	/*
@@ -578,7 +596,7 @@ partial_key:
 	return (0);
 
 complete_key:
-	log_debug("complete key %.*s %#x", (int) size, buf, key);
+	log_debug("complete key %.*s %#llx", (int)size, buf, key);
 
 	/* Remove data from buffer. */
 	evbuffer_drain(tty->event->input, size);
@@ -604,7 +622,7 @@ complete_key:
 	return (1);
 
 discard_key:
-	log_debug("discard key %.*s %#x", (int) size, buf, key);
+	log_debug("discard key %.*s %#llx", (int)size, buf, key);
 
 	/* Remove data from buffer. */
 	evbuffer_drain(tty->event->input, size);
@@ -684,10 +702,10 @@ tty_keys_mouse(struct tty *tty, const char *buf, size_t len, size_t *size)
 					utf8_append(&utf8data, buf[*size]);
 					value = utf8_combine(&utf8data);
 				} else
-					value = (u_char) buf[*size];
+					value = (u_char)buf[*size];
 				(*size)++;
 			} else {
-				value = (u_char) buf[*size];
+				value = (u_char)buf[*size];
 				(*size)++;
 			}
 
diff --git a/utf8.c b/utf8.c
index 9a06c186..e61bf996 100644
--- a/utf8.c
+++ b/utf8.c
@@ -394,6 +394,8 @@ utf8_open(struct utf8_data *utf8data, u_char ch)
 int
 utf8_append(struct utf8_data *utf8data, u_char ch)
 {
+	/* XXX this should do validity checks too! */
+
 	if (utf8data->have >= utf8data->size)
 		fatalx("UTF-8 character overflow");
 	if (utf8data->size > sizeof utf8data->data)
@@ -467,18 +469,46 @@ utf8_combine(const struct utf8_data *utf8data)
 	case 3:
 		value = utf8data->data[2] & 0x3f;
 		value |= (utf8data->data[1] & 0x3f) << 6;
-		value |= (utf8data->data[0] & 0x0f) << 12;
+		value |= (utf8data->data[0] & 0xf) << 12;
 		break;
 	case 4:
 		value = utf8data->data[3] & 0x3f;
 		value |= (utf8data->data[2] & 0x3f) << 6;
 		value |= (utf8data->data[1] & 0x3f) << 12;
-		value |= (utf8data->data[0] & 0x07) << 18;
+		value |= (utf8data->data[0] & 0x7) << 18;
 		break;
 	}
 	return (value);
 }
 
+/* Split a UTF-8 character. */
+int
+utf8_split(u_int uc, struct utf8_data *utf8data)
+{
+	if (uc < 0x7f) {
+		utf8data->size = 1;
+		utf8data->data[0] = uc;
+	} else if (uc < 0x7ff) {
+		utf8data->size = 2;
+		utf8data->data[0] = 0xc0 | ((uc >> 6) & 0x1f);
+		utf8data->data[1] = 0x80 | (uc & 0x3f);
+	} else if (uc < 0xffff) {
+		utf8data->size = 3;
+		utf8data->data[0] = 0xe0 | ((uc >> 12) & 0xf);
+		utf8data->data[1] = 0x80 | ((uc >> 6) & 0x3f);
+		utf8data->data[2] = 0x80 | (uc & 0x3f);
+	} else if (uc < 0x1fffff) {
+		utf8data->size = 4;
+		utf8data->data[0] = 0xf0 | ((uc >> 18) & 0x7);
+		utf8data->data[1] = 0x80 | ((uc >> 12) & 0x3f);
+		utf8data->data[2] = 0x80 | ((uc >> 6) & 0x3f);
+		utf8data->data[3] = 0x80 | (uc & 0x3f);
+	} else
+		return (-1);
+	utf8data->width = utf8_width(utf8data);
+	return (0);
+}
+
 /* Split a two-byte UTF-8 character. */
 u_int
 utf8_split2(u_int uc, u_char *ptr)
diff --git a/window-choose.c b/window-choose.c
index f1c3f94a..fa0e95c8 100644
--- a/window-choose.c
+++ b/window-choose.c
@@ -29,11 +29,11 @@ struct screen *window_choose_init(struct window_pane *);
 void	window_choose_free(struct window_pane *);
 void	window_choose_resize(struct window_pane *, u_int, u_int);
 void	window_choose_key(struct window_pane *, struct client *,
-	    struct session *, int, struct mouse_event *);
+	    struct session *, key_code, struct mouse_event *);
 
 void	window_choose_default_callback(struct window_choose_data *);
 struct window_choose_mode_item *window_choose_get_item(struct window_pane *,
-	    int, struct mouse_event *);
+	    key_code, struct mouse_event *);
 
 void	window_choose_fire_callback(
 	    struct window_pane *, struct window_choose_data *);
@@ -86,9 +86,9 @@ struct window_choose_mode_data {
 
 void	window_choose_free1(struct window_choose_mode_data *);
 int     window_choose_key_index(struct window_choose_mode_data *, u_int);
-int     window_choose_index_key(struct window_choose_mode_data *, int);
+int     window_choose_index_key(struct window_choose_mode_data *, key_code);
 void	window_choose_prompt_input(enum window_choose_input_type,
-	    const char *, struct window_pane *, int);
+	    const char *, struct window_pane *, key_code);
 void	window_choose_reset_top(struct window_pane *, u_int);
 
 void
@@ -314,7 +314,7 @@ window_choose_fire_callback(
 
 void
 window_choose_prompt_input(enum window_choose_input_type input_type,
-    const char *prompt, struct window_pane *wp, int key)
+    const char *prompt, struct window_pane *wp, key_code key)
 {
 	struct window_choose_mode_data	*data = wp->modedata;
 	size_t				 input_len;
@@ -490,7 +490,8 @@ window_choose_expand(struct window_pane *wp, struct session *s, u_int pos)
 }
 
 struct window_choose_mode_item *
-window_choose_get_item(struct window_pane *wp, int key, struct mouse_event *m)
+window_choose_get_item(struct window_pane *wp, key_code key,
+    struct mouse_event *m)
 {
 	struct window_choose_mode_data	*data = wp->modedata;
 	u_int				 x, y, idx;
@@ -509,7 +510,7 @@ window_choose_get_item(struct window_pane *wp, int key, struct mouse_event *m)
 
 void
 window_choose_key(struct window_pane *wp, unused struct client *c,
-    unused struct session *sess, int key, struct mouse_event *m)
+    unused struct session *sess, key_code key, struct mouse_event *m)
 {
 	struct window_choose_mode_data	*data = wp->modedata;
 	struct screen			*s = &data->screen;
@@ -743,8 +744,8 @@ window_choose_key(struct window_pane *wp, unused struct client *c,
 }
 
 void
-window_choose_write_line(
-    struct window_pane *wp, struct screen_write_ctx *ctx, u_int py)
+window_choose_write_line(struct window_pane *wp, struct screen_write_ctx *ctx,
+    u_int py)
 {
 	struct window_choose_mode_data	*data = wp->modedata;
 	struct window_choose_mode_item	*item;
@@ -821,7 +822,7 @@ window_choose_key_index(struct window_choose_mode_data *data, u_int idx)
 }
 
 int
-window_choose_index_key(struct window_choose_mode_data *data, int key)
+window_choose_index_key(struct window_choose_mode_data *data, key_code key)
 {
 	static const char	keys[] = "0123456789"
 	                                 "abcdefghijklmnopqrstuvwxyz"
@@ -834,7 +835,7 @@ window_choose_index_key(struct window_choose_mode_data *data, int key)
 		mkey = mode_key_lookup(&data->mdata, *ptr, NULL);
 		if (mkey != MODEKEY_NONE && mkey != MODEKEY_OTHER)
 			continue;
-		if (key == *ptr)
+		if (key == (key_code)*ptr)
 			return (idx);
 		idx++;
 	}
diff --git a/window-clock.c b/window-clock.c
index e366714b..51f97250 100644
--- a/window-clock.c
+++ b/window-clock.c
@@ -28,7 +28,7 @@ struct screen *window_clock_init(struct window_pane *);
 void	window_clock_free(struct window_pane *);
 void	window_clock_resize(struct window_pane *, u_int, u_int);
 void	window_clock_key(struct window_pane *, struct client *,
-	    struct session *, int, struct mouse_event *);
+	    struct session *, key_code, struct mouse_event *);
 
 void	window_clock_timer_callback(int, short, void *);
 void	window_clock_draw_screen(struct window_pane *);
@@ -186,7 +186,8 @@ window_clock_resize(struct window_pane *wp, u_int sx, u_int sy)
 
 void
 window_clock_key(struct window_pane *wp, unused struct client *c,
-    unused struct session *sess, unused int key, unused struct mouse_event *m)
+    unused struct session *sess, unused key_code key,
+    unused struct mouse_event *m)
 {
 	window_pane_reset_mode(wp);
 }
diff --git a/window-copy.c b/window-copy.c
index c5c053bf..d3e5b7d9 100644
--- a/window-copy.c
+++ b/window-copy.c
@@ -28,9 +28,9 @@ struct screen *window_copy_init(struct window_pane *);
 void	window_copy_free(struct window_pane *);
 void	window_copy_resize(struct window_pane *, u_int, u_int);
 void	window_copy_key(struct window_pane *, struct client *, struct session *,
-	    int, struct mouse_event *);
-int	window_copy_key_input(struct window_pane *, int);
-int	window_copy_key_numeric_prefix(struct window_pane *, int);
+	    key_code, struct mouse_event *);
+int	window_copy_key_input(struct window_pane *, key_code);
+int	window_copy_key_numeric_prefix(struct window_pane *, key_code);
 
 void	window_copy_redraw_selection(struct window_pane *, u_int);
 void	window_copy_redraw_lines(struct window_pane *, u_int, u_int);
@@ -368,7 +368,7 @@ window_copy_resize(struct window_pane *wp, u_int sx, u_int sy)
 
 void
 window_copy_key(struct window_pane *wp, struct client *c, struct session *sess,
-    int key, struct mouse_event *m)
+    key_code key, struct mouse_event *m)
 {
 	const char			*word_separators;
 	struct window_copy_mode_data	*data = wp->modedata;
@@ -800,7 +800,7 @@ input_off:
 }
 
 int
-window_copy_key_input(struct window_pane *wp, int key)
+window_copy_key_input(struct window_pane *wp, key_code key)
 {
 	struct window_copy_mode_data	*data = wp->modedata;
 	struct screen			*s = &data->screen;
@@ -897,7 +897,7 @@ window_copy_key_input(struct window_pane *wp, int key)
 }
 
 int
-window_copy_key_numeric_prefix(struct window_pane *wp, int key)
+window_copy_key_numeric_prefix(struct window_pane *wp, key_code key)
 {
 	struct window_copy_mode_data	*data = wp->modedata;
 	struct screen			*s = &data->screen;
diff --git a/window.c b/window.c
index 49408297..c5f9f176 100644
--- a/window.c
+++ b/window.c
@@ -1102,7 +1102,7 @@ window_pane_reset_mode(struct window_pane *wp)
 
 void
 window_pane_key(struct window_pane *wp, struct client *c, struct session *s,
-    int key, struct mouse_event *m)
+    key_code key, struct mouse_event *m)
 {
 	struct window_pane	*wp2;
 
diff --git a/xterm-keys.c b/xterm-keys.c
index 10d51c78..f1490fcc 100644
--- a/xterm-keys.c
+++ b/xterm-keys.c
@@ -40,11 +40,12 @@
  * We accept any but always output the latter (it comes first in the table).
  */
 
-int	xterm_keys_match(const char *, const char *, size_t, size_t *, u_int *);
-int	xterm_keys_modifiers(const char *, size_t, size_t *, u_int *);
+int	xterm_keys_match(const char *, const char *, size_t, size_t *,
+	    key_code *);
+int	xterm_keys_modifiers(const char *, size_t, size_t *, key_code *);
 
 struct xterm_keys_entry {
-	int		 key;
+	key_code	 key;
 	const char	*template;
 };
 
@@ -115,7 +116,7 @@ const struct xterm_keys_entry xterm_keys_table[] = {
  */
 int
 xterm_keys_match(const char *template, const char *buf, size_t len,
-    size_t *size, u_int *modifiers)
+    size_t *size, key_code *modifiers)
 {
 	size_t	pos;
 	int	retval;
@@ -148,7 +149,8 @@ xterm_keys_match(const char *template, const char *buf, size_t len,
 
 /* Find modifiers from buffer. */
 int
-xterm_keys_modifiers(const char *buf, size_t len, size_t *pos, u_int *modifiers)
+xterm_keys_modifiers(const char *buf, size_t len, size_t *pos,
+    key_code *modifiers)
 {
 	u_int	flags;
 
@@ -179,11 +181,12 @@ xterm_keys_modifiers(const char *buf, size_t len, size_t *pos, u_int *modifiers)
  * key), -1 for not found, 1 for partial match.
  */
 int
-xterm_keys_find(const char *buf, size_t len, size_t *size, int *key)
+xterm_keys_find(const char *buf, size_t len, size_t *size, key_code *key)
 {
 	const struct xterm_keys_entry	*entry;
-	u_int				 i, modifiers;
+	u_int				 i;
 	int				 matched;
+	key_code			 modifiers;
 
 	for (i = 0; i < nitems(xterm_keys_table); i++) {
 		entry = &xterm_keys_table[i];
@@ -201,11 +204,11 @@ xterm_keys_find(const char *buf, size_t len, size_t *size, int *key)
 
 /* Lookup a key number from the table. */
 char *
-xterm_keys_lookup(int key)
+xterm_keys_lookup(key_code key)
 {
 	const struct xterm_keys_entry	*entry;
 	u_int				 i;
-	int				 modifiers;
+	key_code			 modifiers;
 	char				*out;
 
 	modifiers = 1;