diff --git a/Lib/pydoc.py b/Lib/pydoc.py
index dd4fdfdba81..6475decc297 100755
--- a/Lib/pydoc.py
+++ b/Lib/pydoc.py
@@ -1740,6 +1740,7 @@ has the same effect as typing a particular string at the help> prompt.
 
     def help(self, request):
         if type(request) is type(''):
+            request = request.strip()
             if request == 'help': self.intro()
             elif request == 'keywords': self.listkeywords()
             elif request == 'symbols': self.listsymbols()
diff --git a/Lib/test/test_pydoc.py b/Lib/test/test_pydoc.py
index 95a11af9775..03b353910ce 100644
--- a/Lib/test/test_pydoc.py
+++ b/Lib/test/test_pydoc.py
@@ -254,6 +254,12 @@ class PyDocDocTest(unittest.TestCase):
         self.assertEqual(expected, result,
             "documentation for missing module found")
 
+    def test_input_strip(self):
+        missing_module = " test.i_am_not_here "
+        result = str(run_pydoc(missing_module), 'ascii')
+        expected = missing_pattern % missing_module.strip()
+        self.assertEqual(expected, result)
+
 
 class TestDescriptions(unittest.TestCase):
 
diff --git a/Misc/NEWS b/Misc/NEWS
index 626b512ea91..d1117097d64 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -34,6 +34,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #6121: pydoc now ignores leading and trailing spaces in the
+  argument to the 'help' function.
+
 - Issue #6118: urllib.parse.quote_plus ignored the encoding and errors
   arguments for strings with a space in them.