diff --git a/src/urllib3/contrib/appengine.py b/src/urllib3/contrib/appengine.py
index f91bdd6e77..a5a6d91035 100644
--- a/src/urllib3/contrib/appengine.py
+++ b/src/urllib3/contrib/appengine.py
@@ -224,7 +224,7 @@ def urlopen(
                 )
 
         # Check if we should retry the HTTP response.
-        has_retry_after = bool(http_response.getheader("Retry-After"))
+        has_retry_after = bool(http_response.headers.get("Retry-After"))
         if retries.is_retry(method, http_response.status, has_retry_after):
             retries = retries.increment(method, url, response=http_response, _pool=self)
             log.debug("Retry: %s", url)
diff --git a/src/urllib3/contrib/ntlmpool.py b/src/urllib3/contrib/ntlmpool.py
index 41a8fd174c..471665754e 100644
--- a/src/urllib3/contrib/ntlmpool.py
+++ b/src/urllib3/contrib/ntlmpool.py
@@ -69,7 +69,7 @@ def _new_conn(self):
         log.debug("Request headers: %s", headers)
         conn.request("GET", self.authurl, None, headers)
         res = conn.getresponse()
-        reshdr = dict(res.getheaders())
+        reshdr = dict(res.headers)
         log.debug("Response status: %s %s", res.status, res.reason)
         log.debug("Response headers: %s", reshdr)
         log.debug("Response data: %s [...]", res.read(100))
@@ -101,7 +101,7 @@ def _new_conn(self):
         conn.request("GET", self.authurl, None, headers)
         res = conn.getresponse()
         log.debug("Response status: %s %s", res.status, res.reason)
-        log.debug("Response headers: %s", dict(res.getheaders()))
+        log.debug("Response headers: %s", dict(res.headers))
         log.debug("Response data: %s [...]", res.read()[:100])
         if res.status != 200:
             if res.status == 401: