diff --git a/keybinding.c b/keybinding.c
index 9564dfe6..177637c4 100644
--- a/keybinding.c
+++ b/keybinding.c
@@ -127,6 +127,7 @@ luaA_keybinding_gc(lua_State *L)
 {
     keybinding_t **keybinding = luaL_checkudata(L, 1, "keybinding");
     keybinding_unref(keybinding);
+    keybinding = NULL;
     return 0;
 }
 
diff --git a/statusbar.c b/statusbar.c
index 1df9222c..d35a8304 100644
--- a/statusbar.c
+++ b/statusbar.c
@@ -503,6 +503,7 @@ luaA_statusbar_gc(lua_State *L)
 {
     statusbar_t **sb = luaL_checkudata(L, 1, "statusbar");
     statusbar_unref(sb);
+    *sb = NULL;
     return 0;
 }
 
diff --git a/tag.c b/tag.c
index cb17cb8a..2ed136bf 100644
--- a/tag.c
+++ b/tag.c
@@ -484,6 +484,7 @@ luaA_tag_gc(lua_State *L)
 {
     tag_t **tag = luaL_checkudata(L, 1, "tag");
     tag_unref(tag);
+    *tag = NULL;
     return 0;
 }
 
diff --git a/titlebar.c b/titlebar.c
index 5ae5bae0..011b1288 100644
--- a/titlebar.c
+++ b/titlebar.c
@@ -527,6 +527,7 @@ luaA_titlebar_gc(lua_State *L)
 {
     titlebar_t **titlebar = luaL_checkudata(L, 1, "titlebar");
     titlebar_unref(titlebar);
+    *titlebar = NULL;
     return 0;
 }
 
diff --git a/widget.c b/widget.c
index 31dcf07e..ad21f558 100644
--- a/widget.c
+++ b/widget.c
@@ -438,6 +438,7 @@ luaA_widget_gc(lua_State *L)
 {
     widget_t **widget = luaL_checkudata(L, 1, "widget");
     widget_unref(widget);
+    *widget = NULL;
     return 0;
 }