diff --git a/gtk/gtktoolbutton.c b/gtk/gtktoolbutton.c
index 4286a8e2d9..5f25715863 100644
--- a/gtk/gtktoolbutton.c
+++ b/gtk/gtktoolbutton.c
@@ -514,7 +514,11 @@ gtk_tool_button_construct_contents (GtkToolItem *tool_item)
 	{
           box = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 0);
 	  if (icon)
-            gtk_box_pack_start (GTK_BOX (box), icon);
+            {
+              gtk_box_pack_start (GTK_BOX (box), icon);
+              if (!label)
+                gtk_widget_set_hexpand (icon, TRUE);
+            }
 	  if (label)
             gtk_box_pack_end (GTK_BOX (box), label);
 	}
@@ -522,7 +526,11 @@ gtk_tool_button_construct_contents (GtkToolItem *tool_item)
 	{
           box = gtk_box_new (GTK_ORIENTATION_VERTICAL, 0);
 	  if (icon)
-            gtk_box_pack_end (GTK_BOX (box), icon);
+            {
+              gtk_box_pack_end (GTK_BOX (box), icon);
+              if (!label)
+                gtk_widget_set_vexpand (icon, TRUE);
+            }
 	  if (label)
             gtk_box_pack_start (GTK_BOX (box), label);
 	}