diff --git a/doc/source/reference/drivers/gerrit.rst b/doc/source/reference/drivers/gerrit.rst
index 61b45877e9..cc924eb4d6 100644
--- a/doc/source/reference/drivers/gerrit.rst
+++ b/doc/source/reference/drivers/gerrit.rst
@@ -103,18 +103,19 @@ The supported options in ``zuul.conf`` connections are:
       section of the ``Settings`` page in Gerrit.
 
    .. attr:: auth_type
-      :default: digest
+      :default: basic
 
       The HTTP authentication mechanism.
 
-      .. value:: digest
-
-         HTTP Digest authentication; the default for most Gerrit
-         installations.
-
       .. value:: basic
 
-         HTTP Basic authentication.
+         HTTP Basic authentication; the default for most Gerrit
+         installations.
+
+      .. value:: digest
+
+         HTTP Digest authentication; only used in versions of Gerrit
+         prior to 2.15.
 
       .. value:: form
 
diff --git a/releasenotes/notes/gerrit-default-auth-c6165622bffc6434.yaml b/releasenotes/notes/gerrit-default-auth-c6165622bffc6434.yaml
new file mode 100644
index 0000000000..19a358989a
--- /dev/null
+++ b/releasenotes/notes/gerrit-default-auth-c6165622bffc6434.yaml
@@ -0,0 +1,8 @@
+upgrade:
+  - |
+    The default for :attr:`<gerrit connection>.auth_type` has changed from
+    ``digest`` to ``basic``.  Digest authentication has not been supported
+    in Gerrit since version 2.15.
+
+    If your Zuul connects to an older version of Gerrit via HTTP
+    authentication, you may now need to explicitly set this value.
diff --git a/zuul/driver/gerrit/gerritconnection.py b/zuul/driver/gerrit/gerritconnection.py
index 8b9299db46..7dea617ea8 100644
--- a/zuul/driver/gerrit/gerritconnection.py
+++ b/zuul/driver/gerrit/gerritconnection.py
@@ -483,12 +483,12 @@ class GerritConnection(BaseConnection):
                 zuul_version.release_string,
                 requests.utils.default_user_agent())
             self.session = requests.Session()
-            if self.auth_type == 'basic':
-                authclass = requests.auth.HTTPBasicAuth
+            if self.auth_type == 'digest':
+                authclass = requests.auth.HTTPDigestAuth
             elif self.auth_type == 'form':
                 authclass = FormAuth
             else:
-                authclass = requests.auth.HTTPDigestAuth
+                authclass = requests.auth.HTTPBasicAuth
             self.auth = authclass(
                 self.user, self.password)