diff --git a/content/base/public/nsDeprecatedOperationList.h b/content/base/public/nsDeprecatedOperationList.h
index af6a98d59844..e31a2448a00e 100644
--- a/content/base/public/nsDeprecatedOperationList.h
+++ b/content/base/public/nsDeprecatedOperationList.h
@@ -28,3 +28,4 @@ DEPRECATED_OPERATION(NoExposedProps)
 DEPRECATED_OPERATION(MutationEvent)
 DEPRECATED_OPERATION(MozSlice)
 DEPRECATED_OPERATION(Components)
+DEPRECATED_OPERATION(PrefixedVisibilityAPI)
diff --git a/content/base/src/nsDocument.cpp b/content/base/src/nsDocument.cpp
index 842f5b0a6b46..e2bc9b7e32c0 100644
--- a/content/base/src/nsDocument.cpp
+++ b/content/base/src/nsDocument.cpp
@@ -9527,6 +9527,7 @@ nsDocument::PostVisibilityUpdateEvent()
 NS_IMETHODIMP
 nsDocument::GetMozHidden(bool* aHidden)
 {
+  WarnOnceAbout(ePrefixedVisibilityAPI);
   return GetHidden(aHidden);
 }
 
@@ -9540,6 +9541,7 @@ nsDocument::GetHidden(bool* aHidden)
 NS_IMETHODIMP
 nsDocument::GetMozVisibilityState(nsAString& aState)
 {
+  WarnOnceAbout(ePrefixedVisibilityAPI);
   return GetVisibilityState(aState);
 }
 
diff --git a/dom/locales/en-US/chrome/dom/dom.properties b/dom/locales/en-US/chrome/dom/dom.properties
index ca38638a3718..cad8698cfbe1 100644
--- a/dom/locales/en-US/chrome/dom/dom.properties
+++ b/dom/locales/en-US/chrome/dom/dom.properties
@@ -114,3 +114,5 @@ MutationEventWarning=Use of Mutation Events is deprecated. Use MutationObserver
 MozSliceWarning=Use of mozSlice on the Blob object is deprecated.  Use slice instead.
 # LOCALIZATION NOTE: Do not translate "Components"
 ComponentsWarning=The Components object is deprecated. It will soon be removed.
+# LOCALIZATION NOTE: Do not translate "mozHidden", "mozVisibilityState", "hidden", or "visibilityState"
+PrefixedVisibilityApiWarning='mozHidden' and 'mozVisibilityState' are deprecated.  Please use the unprefixed 'hidden' and 'visibilityState' instead.