diff --git a/src/video/x11/SDL_x11events.c b/src/video/x11/SDL_x11events.c
index a4e5d9caf6..364e05a779 100644
--- a/src/video/x11/SDL_x11events.c
+++ b/src/video/x11/SDL_x11events.c
@@ -988,8 +988,11 @@ void X11_HandleKeyEvent(SDL_VideoDevice *_this, SDL_WindowData *windowdata, SDL_
     }
 
     if (pressed) {
-        X11_HandleModifierKeys(videodata, scancode, true, true);
-        SDL_SendKeyboardKeyIgnoreModifiers(timestamp, keyboardID, keycode, scancode, true);
+        // Duplicate events may be sent when an IME is active; don't send multiple keydown events for the same serial.
+        if (videodata->last_key_down_serial != xevent->xkey.serial) {
+            X11_HandleModifierKeys(videodata, scancode, true, true);
+            SDL_SendKeyboardKeyIgnoreModifiers(timestamp, keyboardID, keycode, scancode, true);
+        }
 
         // Synthesize a text event if the IME didn't consume a printable character
         if (*text && !(SDL_GetModState() & (SDL_KMOD_CTRL | SDL_KMOD_ALT))) {
@@ -999,6 +1002,7 @@ void X11_HandleKeyEvent(SDL_VideoDevice *_this, SDL_WindowData *windowdata, SDL_
         }
 
         X11_UpdateUserTime(windowdata, xevent->xkey.time);
+        videodata->last_key_down_serial = xevent->xkey.serial;
     } else {
         if (X11_KeyRepeat(display, xevent)) {
             // We're about to get a repeated key down, ignore the key up
diff --git a/src/video/x11/SDL_x11video.h b/src/video/x11/SDL_x11video.h
index a336a800f5..d5a9299b4e 100644
--- a/src/video/x11/SDL_x11video.h
+++ b/src/video/x11/SDL_x11video.h
@@ -140,6 +140,8 @@ struct SDL_VideoData
     int xinput_master_pointer_device;
     bool xinput_hierarchy_changed;
 
+    unsigned long last_key_down_serial;
+
     int xrandr_event_base;
     struct
     {