diff --git a/README.md b/README.md
index 41f776c8..26ca38f9 100644
--- a/README.md
+++ b/README.md
@@ -77,6 +77,7 @@ GLFW bundles a number of dependencies in the `deps/` directory.
  - [X11] Bugfix: Character input via XIM did not work in many cases
  - [X11] Bugfix: No fallback existed for missing `_NET_ACTIVE_WINDOW` support
  - [X11] Bugfix: Some significant window focus events were ignored
+ - [X11] Bugfix: Auto-iconification of full screen windows was not implemented
  - [WGL] Removed `GLFW_USE_DWM_SWAP_INTERVAL` compile-time option
  - [WGL] Bugfix: Swap interval was ignored when DWM was enabled
  - [GLX] Added dependency on `libdl` on systems where it provides `dlopen`
diff --git a/src/x11_window.c b/src/x11_window.c
index 8bb6da76..747da31a 100644
--- a/src/x11_window.c
+++ b/src/x11_window.c
@@ -1234,6 +1234,9 @@ static void processEvent(XEvent *event)
             if (window->cursorMode == GLFW_CURSOR_DISABLED)
                 disableCursor(window);
 
+            if (window->monitor && window->autoIconify)
+                enterFullscreenMode(window);
+
             _glfwInputWindowFocus(window, GL_TRUE);
             return;
         }
@@ -1254,6 +1257,12 @@ static void processEvent(XEvent *event)
             if (window->cursorMode == GLFW_CURSOR_DISABLED)
                 restoreCursor(window);
 
+            if (window->monitor && window->autoIconify)
+            {
+                _glfwPlatformIconifyWindow(window);
+                leaveFullscreenMode(window);
+            }
+
             _glfwInputWindowFocus(window, GL_FALSE);
             return;
         }