diff --git a/calendar/locales/en-US/chrome/calendar/calendar.properties b/calendar/locales/en-US/chrome/calendar/calendar.properties
index d6e1f893e58..1450e5afa33 100644
--- a/calendar/locales/en-US/chrome/calendar/calendar.properties
+++ b/calendar/locales/en-US/chrome/calendar/calendar.properties
@@ -64,6 +64,11 @@ statusNeedsAction=Needs Action
 statusInProcess  =In Process
 statusCompleted  =Completed
 
+# Task priority, these should match the priority.level.* labels in calendar.dtd
+highPriority=High
+mediumPriority=Medium
+lowPriority=Low
+
 noEventsOrTasksToImport=No events or tasks to import\nfrom file "%1$S".
 noEventsToSave=No events selected to save.