diff --git a/include/class.collaborator.php b/include/class.collaborator.php
index dc35a436f06c3ee2f5b2e0c1c9cb5847be864970..65deaf8e4ec06c79d77293847467d8a65ab6e4d2 100644
--- a/include/class.collaborator.php
+++ b/include/class.collaborator.php
@@ -41,7 +41,7 @@ implements EmailContact, ITicketUser {
         return Format::htmlchars($this->toString());
     }
     function toString() {
-        return sprintf('%s <%s>', $this->getName(), $this->getEmail());
+        return sprintf('"%s" <%s>', $this->getName(), $this->getEmail());
     }
 
     function getId() {
diff --git a/include/class.user.php b/include/class.user.php
index 53a8627c3bd4d95e319d86e26d9e1f8498f5a4d4..0fa35e4a14d62514632bcf163f80fc25e216b49c 100644
--- a/include/class.user.php
+++ b/include/class.user.php
@@ -678,7 +678,7 @@ implements TemplateVariable {
                 $this->getDomain());
 
         if ($this->getName())
-            $this->address = sprintf('%s <%s>',
+            $this->address = sprintf('"%s" <%s>',
                     $this->getName(),
                     $this->email);
     }