diff --git a/src/applications/differential/customfield/DifferentialTestPlanField.php b/src/applications/differential/customfield/DifferentialTestPlanField.php
index c4c8cf7943..efc3bfc1a0 100644
--- a/src/applications/differential/customfield/DifferentialTestPlanField.php
+++ b/src/applications/differential/customfield/DifferentialTestPlanField.php
@@ -44,7 +44,7 @@ final class DifferentialTestPlanField
   protected function getCoreFieldRequiredErrorString() {
     return pht(
       'You must provide a test plan. Describe the actions you performed '.
-      'to verify the behvaior of this change.');
+      'to verify the behavior of this change.');
   }
 
   public function readValueFromRequest(AphrontRequest $request) {