diff --git a/src/msw/toolbar.cpp b/src/msw/toolbar.cpp
index 3cfee08579..6875263f90 100644
--- a/src/msw/toolbar.cpp
+++ b/src/msw/toolbar.cpp
@@ -1018,13 +1018,15 @@ bool wxToolBar::Realize()
                         break;
                 }
 
-                // Instead of using fixed widths for all buttons, size them
+                // When toolbar has wxTB_HORZ_LAYOUT style then
+                // instead of using fixed widths for all buttons, size them
                 // automatically according to the size of their bitmap and text
-                // label, if present. This particularly matters for toolbars
-                // with the wxTB_HORZ_LAYOUT style: they look hideously ugly
-                // without autosizing when the labels have even slightly
-                // different lengths.
-                button.fsStyle |= TBSTYLE_AUTOSIZE;
+                // label, if present. They look hideously ugly without autosizing
+                // when the labels have even slightly different lengths.
+                if ( !IsVertical() )
+                {
+                    button.fsStyle |= TBSTYLE_AUTOSIZE;
+                }
 
                 bitmapId++;
                 break;