diff --git a/django/core/mail/backends/smtp.py b/django/core/mail/backends/smtp.py
index df47d4e823..c9e0a18728 100644
--- a/django/core/mail/backends/smtp.py
+++ b/django/core/mail/backends/smtp.py
@@ -56,6 +56,8 @@ class EmailBackend(BaseEmailBackend):
                 self.connection.ehlo()
                 self.connection.starttls()
                 self.connection.ehlo()
+            if self.username and self.password:
+                self.connection.login(self.username, self.password)
         except smtplib.SMTPException:
             if not self.fail_silently:
                 raise
diff --git a/tests/mail/tests.py b/tests/mail/tests.py
index a380ecf3d7..4fcea7b8ca 100644
--- a/tests/mail/tests.py
+++ b/tests/mail/tests.py
@@ -880,6 +880,16 @@ class SMTPBackendTests(BaseEmailBackendTests, SimpleTestCase):
         self.assertEqual(backend.username, '')
         self.assertEqual(backend.password, '')
 
+    def test_auth_attempted(self):
+        """
+        Test that opening the backend with non empty username/password tries
+        to authenticate against the SMTP server.
+        """
+        backend = smtp.EmailBackend(
+            username='not empty username', password='not empty password')
+        self.assertRaisesMessage(SMTPException,
+            'SMTP AUTH extension not supported by server.', backend.open)
+
     def test_server_stopped(self):
         """
         Test that closing the backend while the SMTP server is stopped doesn't