diff --git a/Lib/pydoc.py b/Lib/pydoc.py
index dda0208edf7..3afb9814d25 100755
--- a/Lib/pydoc.py
+++ b/Lib/pydoc.py
@@ -422,7 +422,7 @@ class HTMLDoc(Doc):
     def page(self, title, contents):
         """Format an HTML page."""
         return '''
-<!doctype html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
 <html><head><title>Python: %s</title>
 </head><body bgcolor="#f0f0f8">
 %s
