diff --git a/widget/src/mac/nsMacWindow.cpp b/widget/src/mac/nsMacWindow.cpp
index 9edd6612079a..ab461586c6b5 100644
--- a/widget/src/mac/nsMacWindow.cpp
+++ b/widget/src/mac/nsMacWindow.cpp
@@ -232,6 +232,21 @@ NS_IMETHODIMP nsMacWindow::Resize(PRUint32 aWidth, PRUint32 aHeight, PRBool aRep
 	return NS_OK;
 }
 
+//-------------------------------------------------------------------------
+//
+// Set this window's title
+//
+//-------------------------------------------------------------------------
+NS_IMETHODIMP nsMacWindow::SetTitle(const nsString& aTitle)
+{
+	Str255 title;
+	title[0] = aTitle.Length();
+	aTitle.ToCString((char*)title + 1, sizeof(title) - 1);
+	::SetWTitle(mWindowPtr, title);
+	return NS_OK;
+}
+
+
 //-------------------------------------------------------------------------
 //
 // Handle OS events
diff --git a/widget/src/mac/nsMacWindow.h b/widget/src/mac/nsMacWindow.h
index 7a7b59a18b5b..b3cba533efe7 100644
--- a/widget/src/mac/nsMacWindow.h
+++ b/widget/src/mac/nsMacWindow.h
@@ -77,6 +77,8 @@ public:
     NS_IMETHOD            	Move(PRUint32 aX, PRUint32 aY);
     NS_IMETHOD            	Resize(PRUint32 aWidth,PRUint32 aHeight, PRBool aRepaint);
 
+	NS_IMETHOD              SetTitle(const nsString& aTitle);
+
 		virtual PRBool					HandleOSEvent(
 																		EventRecord&		aOSEvent);