diff --git a/Lib/smtplib.py b/Lib/smtplib.py
index 759b77e47fa..09b4ea64796 100755
--- a/Lib/smtplib.py
+++ b/Lib/smtplib.py
@@ -866,6 +866,10 @@ class SMTP:
     def quit(self):
         """Terminate the SMTP session."""
         res = self.docmd("quit")
+        # A new EHLO is required after reconnecting with connect()
+        self.ehlo_resp = self.helo_resp = None
+        self.esmtp_features = {}
+        self.does_esmtp = False
         self.close()
         return res
 
diff --git a/Lib/test/test_smtplib.py b/Lib/test/test_smtplib.py
index 16e90f4ab32..95a9dbe9122 100644
--- a/Lib/test/test_smtplib.py
+++ b/Lib/test/test_smtplib.py
@@ -858,6 +858,21 @@ class SMTPSimTests(unittest.TestCase):
             self.assertIn(sim_auth_login_password, str(err))
         smtp.close()
 
+    def test_quit_resets_greeting(self):
+        smtp = smtplib.SMTP(HOST, self.port,
+                            local_hostname='localhost',
+                            timeout=15)
+        code, message = smtp.ehlo()
+        self.assertEqual(code, 250)
+        self.assertIn('size', smtp.esmtp_features)
+        smtp.quit()
+        self.assertNotIn('size', smtp.esmtp_features)
+        smtp.connect(HOST, self.port)
+        self.assertNotIn('size', smtp.esmtp_features)
+        smtp.ehlo_or_helo_if_needed()
+        self.assertIn('size', smtp.esmtp_features)
+        smtp.quit()
+
     def test_with_statement(self):
         with smtplib.SMTP(HOST, self.port) as smtp:
             code, message = smtp.noop()
diff --git a/Misc/NEWS b/Misc/NEWS
index ab5eee6bb90..5111b8aa160 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -27,6 +27,10 @@ Core and Builtins
 Library
 -------
 
+- Issue #22216: smtplib now resets its state more completely after a quit.  The
+  most obvious consequence of the previous behavior was a STARTTLS failure
+  during a connect/starttls/quit/connect/starttls sequence.
+
 - Issue #22185: Fix an occasional RuntimeError in threading.Condition.wait()
   caused by mutation of the waiters queue without holding the lock.  Patch
   by Doug Zongker.