diff --git a/Lib/pydoc.py b/Lib/pydoc.py
index 0b56f254de0..bfb0a03378c 100755
--- a/Lib/pydoc.py
+++ b/Lib/pydoc.py
@@ -956,7 +956,7 @@ class HTMLDoc(Doc):
         if not argspec:
             argspec = '(...)'
 
-        decl = title + argspec + (note and self.grey(
+        decl = title + self.escape(argspec) + (note and self.grey(
                '<font face="helvetica, arial">%s</font>' % note))
 
         if skipdocs: