diff --git a/src/platform/platform.h b/src/platform/platform.h
index 98bd6b0041..4457d3a32a 100644
--- a/src/platform/platform.h
+++ b/src/platform/platform.h
@@ -80,6 +80,7 @@ void platform_process_messages();
 int platform_scancode_to_rct_keycode(int sdl_key);
 void platform_start_text_input(char* buffer, int max_length);
 void platform_stop_text_input();
+void platform_update_config_window_size();
 
 // Platform specific definitions
 char platform_get_path_separator();
diff --git a/src/platform/shared.c b/src/platform/shared.c
index 4361a35451..47129bac09 100644
--- a/src/platform/shared.c
+++ b/src/platform/shared.c
@@ -453,6 +453,23 @@ static void platform_close_window()
 	platform_unload_cursors();
 }
 
+void platform_update_config_window_size()
+{
+	// Check if the window has been resized in windowed mode and update the config file accordingly
+	// This is called in rct2_update_2 and is only called after resizing a window has finished
+	int width, height;
+	uint32 flags = SDL_GetWindowFlags(gWindow);
+	if ((flags & (SDL_WINDOW_MAXIMIZED | SDL_WINDOW_MINIMIZED |
+				SDL_WINDOW_FULLSCREEN | SDL_WINDOW_FULLSCREEN_DESKTOP)) == 0) {
+		SDL_GetWindowSize(gWindow, &width, &height);
+		if (width != gConfigGeneral.window_width || height != gConfigGeneral.window_height) {
+			gConfigGeneral.window_width = width;
+			gConfigGeneral.window_height = height;
+			config_save_default();
+		}
+	}
+}
+
 void platform_init()
 {
 	platform_create_window();
diff --git a/src/rct2.c b/src/rct2.c
index f70848a2a7..c91f007473 100644
--- a/src/rct2.c
+++ b/src/rct2.c
@@ -345,6 +345,9 @@ void rct2_update_2()
 		title_update();
 	else
 		game_update();
+
+	// Update the windowed mode size in the config file if needed
+	platform_update_config_window_size();
 }
 
 void rct2_endupdate()