diff --git a/conf/default.conf.php b/conf/default.conf.php
--- a/conf/default.conf.php
+++ b/conf/default.conf.php
@@ -314,6 +314,7 @@
   'phpmailer.mailer'            =>  'smtp',
   'phpmailer.smtp-host'         =>  '',
   'phpmailer.smtp-port'         =>  25,
+  'phpmailer.smtp-timeout'      =>  10,
 
   // When using PHPMailer with SMTP, you can set this to one of "tls" or "ssl"
   // to use TLS or SSL. Leave it blank for vanilla SMTP. If you're sending
diff --git a/src/applications/config/option/PhabricatorPHPMailerConfigOptions.php b/src/applications/config/option/PhabricatorPHPMailerConfigOptions.php
--- a/src/applications/config/option/PhabricatorPHPMailerConfigOptions.php
+++ b/src/applications/config/option/PhabricatorPHPMailerConfigOptions.php
@@ -26,6 +26,8 @@
         ->setDescription(pht('Host for SMTP.')),
       $this->newOption('phpmailer.smtp-port', 'int', 25)
         ->setDescription(pht('Port for SMTP.')),
+      $this->newOption('phpmailer.smtp-timeout', 'int', 10)
+        ->setDescription(pht('Timeout in seconds for SMTP.')),
       // TODO: Implement "enum"? Valid values are empty, 'tls', or 'ssl'.
       $this->newOption('phpmailer.smtp-protocol', 'string', null)
         ->setSummary(pht('Configure TLS or SSL for SMTP.'))
diff --git a/src/applications/metamta/adapter/PhabricatorMailImplementationPHPMailerAdapter.php b/src/applications/metamta/adapter/PhabricatorMailImplementationPHPMailerAdapter.php
--- a/src/applications/metamta/adapter/PhabricatorMailImplementationPHPMailerAdapter.php
+++ b/src/applications/metamta/adapter/PhabricatorMailImplementationPHPMailerAdapter.php
@@ -23,6 +23,8 @@
       $this->mailer->IsSMTP();
       $this->mailer->Host = PhabricatorEnv::getEnvConfig('phpmailer.smtp-host');
       $this->mailer->Port = PhabricatorEnv::getEnvConfig('phpmailer.smtp-port');
+      $this->mailer->Timeout =
+        PhabricatorEnv::getEnvConfig('phpmailer.smtp-timeout');
       $user = PhabricatorEnv::getEnvConfig('phpmailer.smtp-user');
       if ($user) {
         $this->mailer->SMTPAuth = true;
diff --git a/src/docs/user/configuration/configuring_outbound_email.diviner b/src/docs/user/configuration/configuring_outbound_email.diviner
--- a/src/docs/user/configuration/configuring_outbound_email.diviner
+++ b/src/docs/user/configuration/configuring_outbound_email.diviner
@@ -91,6 +91,8 @@
   - **phpmailer.mailer**: set to "smtp".
   - **phpmailer.smtp-host**: set to hostname of your smtp server.
   - **phpmailer.smtp-port**: set to port of your smtp server.
+  - **phpmailer.smtp-timeout**: set to the timeout used for communicating with
+    your smtp server.
   - **phpmailer.smtp-user**: set to your username used for authentication.
   - **phpmailer.smtp-password**: set to your password used for authentication.