diff --git a/src/applications/auth/adapter/PhutilGitHubAuthAdapter.php b/src/applications/auth/adapter/PhutilGitHubAuthAdapter.php
index 7fa8a660fa..a9d4c849d5 100644
--- a/src/applications/auth/adapter/PhutilGitHubAuthAdapter.php
+++ b/src/applications/auth/adapter/PhutilGitHubAuthAdapter.php
@@ -1,72 +1,76 @@
 <?php
 
 /**
  * Authentication adapter for Github OAuth2.
  */
 final class PhutilGitHubAuthAdapter extends PhutilOAuthAuthAdapter {
 
   public function getAdapterType() {
     return 'github';
   }
 
   public function getAdapterDomain() {
     return 'github.com';
   }
 
   public function getAccountID() {
     return $this->getOAuthAccountData('id');
   }
 
   public function getAccountEmail() {
     return $this->getOAuthAccountData('email');
   }
 
   public function getAccountName() {
     return $this->getOAuthAccountData('login');
   }
 
   public function getAccountImageURI() {
     return $this->getOAuthAccountData('avatar_url');
   }
 
   public function getAccountURI() {
     $name = $this->getAccountName();
     if (strlen($name)) {
       return 'https://github.com/'.$name;
     }
     return null;
   }
 
   public function getAccountRealName() {
     return $this->getOAuthAccountData('name');
   }
 
   protected function getAuthenticateBaseURI() {
     return 'https://github.com/login/oauth/authorize';
   }
 
   protected function getTokenBaseURI() {
     return 'https://github.com/login/oauth/access_token';
   }
 
   protected function loadOAuthAccountData() {
     $uri = new PhutilURI('https://api.github.com/user');
-    $uri->replaceQueryParam('access_token', $this->getAccessToken());
 
     $future = new HTTPSFuture($uri);
 
     // NOTE: GitHub requires a User-Agent string.
     $future->addHeader('User-Agent', __CLASS__);
 
+    // See T13485. Circa early 2020, GitHub has deprecated use of the
+    // "access_token" URI parameter.
+    $token_header = sprintf('token %s', $this->getAccessToken());
+    $future->addHeader('Authorization', $token_header);
+
     list($body) = $future->resolvex();
 
     try {
       return phutil_json_decode($body);
     } catch (PhutilJSONParserException $ex) {
       throw new PhutilProxyException(
         pht('Expected valid JSON response from GitHub account data request.'),
         $ex);
     }
   }
 
 }