diff --git a/Lib/rlcompleter.py b/Lib/rlcompleter.py
index 931edcc4c3a..bca4a7bc521 100644
--- a/Lib/rlcompleter.py
+++ b/Lib/rlcompleter.py
@@ -75,9 +75,12 @@ class Completer:
 
         if not text.strip():
             if state == 0:
-                readline.insert_text('\t')
-                readline.redisplay()
-                return ''
+                if _readline_available:
+                    readline.insert_text('\t')
+                    readline.redisplay()
+                    return ''
+                else:
+                    return '\t'
             else:
                 return None
 
@@ -192,10 +195,11 @@ def get_class_members(klass):
 try:
     import readline
 except ImportError:
-    pass
+    _readline_available = False
 else:
     readline.set_completer(Completer().complete)
     # Release references early at shutdown (the readline module's
     # contents are quasi-immortal, and the completer function holds a
     # reference to globals).
     atexit.register(lambda: readline.set_completer(None))
+    _readline_available = True
diff --git a/Lib/test/test_rlcompleter.py b/Lib/test/test_rlcompleter.py
index 208c0545c44..0dc1080ca32 100644
--- a/Lib/test/test_rlcompleter.py
+++ b/Lib/test/test_rlcompleter.py
@@ -101,6 +101,7 @@ class TestRlcompleter(unittest.TestCase):
         completer = rlcompleter.Completer(dict(f=Foo()))
         self.assertEqual(completer.complete('f.', 0), 'f.bar')
 
+    @unittest.mock.patch('rlcompleter._readline_available', False)
     def test_complete(self):
         completer = rlcompleter.Completer()
         self.assertEqual(completer.complete('', 0), '\t')