diff --git a/cmd-set-window-option.c b/cmd-set-window-option.c
index 76d00e19..1ac62147 100644
--- a/cmd-set-window-option.c
+++ b/cmd-set-window-option.c
@@ -64,6 +64,7 @@ const struct set_option_entry set_window_option_table[] = {
 	{ "monitor-activity", SET_OPTION_FLAG, 0, 0, NULL },
 	{ "monitor-content", SET_OPTION_STRING, 0, 0, NULL },
 	{ "remain-on-exit", SET_OPTION_FLAG, 0, 0, NULL },
+	{ "synchronize-panes", SET_OPTION_FLAG, 0, 0, NULL },
 	{ "utf8", SET_OPTION_FLAG, 0, 0, NULL },
 	{ "window-status-attr", SET_OPTION_ATTRIBUTES, 0, 0, NULL },
 	{ "window-status-bg", SET_OPTION_COLOUR, 0, 0, NULL },
diff --git a/tmux.1 b/tmux.1
index 938dba43..397ff83b 100644
--- a/tmux.1
+++ b/tmux.1
@@ -1662,6 +1662,11 @@ The window may be reactivated with the
 .Ic respawn-window
 command.
 .Pp
+.It Xo Ic synchronize-panes
+.Op Ic on | off
+.Xc
+Duplicate input to any pane to all other panes in the same window, except
+for panes that are not in output mode.
 .It Xo Ic utf8
 .Op Ic on | off
 .Xc
diff --git a/tmux.c b/tmux.c
index 5673282f..eed7e9e1 100644
--- a/tmux.c
+++ b/tmux.c
@@ -441,6 +441,7 @@ main(int argc, char **argv)
 	options_set_number(wo, "window-status-fg", 8);
 	options_set_number(wo, "xterm-keys", 0);
  	options_set_number(wo, "remain-on-exit", 0);
+	options_set_number(wo, "synchronize-panes", 0);
 
  	if (flags & IDENTIFY_UTF8) {
 		options_set_number(so, "status-utf8", 1);
diff --git a/window.c b/window.c
index b663acf3..9d2f3975 100644
--- a/window.c
+++ b/window.c
@@ -610,14 +610,26 @@ window_pane_parse(struct window_pane *wp)
 void
 window_pane_key(struct window_pane *wp, struct client *c, int key)
 {
+	struct window_pane	*wp2;
+
 	if (wp->fd == -1 || !window_pane_visible(wp))
 		return;
 
 	if (wp->mode != NULL) {
 		if (wp->mode->key != NULL)
 			wp->mode->key(wp, c, key);
-	} else
-		input_key(wp, key);
+		return;
+	} 
+
+	input_key(wp, key);
+	if (options_get_number(&wp->window->options, "synchronize-panes")) {
+		TAILQ_FOREACH(wp2, &wp->window->panes, entry) {
+			if (wp2 == wp || wp2->mode != NULL)
+				continue;
+			if (wp2->fd != -1 && window_pane_visible(wp2))
+				input_key(wp2, key);
+		}
+	}
 }
 
 void