diff --git a/src/gtk/timer.cpp b/src/gtk/timer.cpp
index a8514f8cd1..48313ee6ad 100644
--- a/src/gtk/timer.cpp
+++ b/src/gtk/timer.cpp
@@ -41,7 +41,12 @@ extern "C" gint timeout_callback( gpointer data )
     gdk_threads_leave();
 
     if ( timer->IsOneShot() )
+    {
+        // This sets m_tag to -1
+        timer->Stop();
+        
         return FALSE;
+    }
 
     return TRUE;
 }
diff --git a/src/gtk1/timer.cpp b/src/gtk1/timer.cpp
index a8514f8cd1..48313ee6ad 100644
--- a/src/gtk1/timer.cpp
+++ b/src/gtk1/timer.cpp
@@ -41,7 +41,12 @@ extern "C" gint timeout_callback( gpointer data )
     gdk_threads_leave();
 
     if ( timer->IsOneShot() )
+    {
+        // This sets m_tag to -1
+        timer->Stop();
+        
         return FALSE;
+    }
 
     return TRUE;
 }