diff --git a/layout/reftests/font-matching/arial-arabic-ref.html b/layout/reftests/font-matching/arial-arabic-ref.html
new file mode 100644
index 000000000000..f5665f6c53e4
--- /dev/null
+++ b/layout/reftests/font-matching/arial-arabic-ref.html
@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>Bug 769475 - test for italicized Arabic script in Arial</title>
+<style type="text/css">
+body {
+  font-family: arial, serif;
+  font-size: 36px;
+  line-height: 72px;
+}
+span {
+  color: white;
+}
+</style>
+</head>
+<body lang="ar">
+<!-- the white span should have the same width whether it's italicized or not,
+  -- as Arial does not have Arabic characters in the italic face but we should
+  -- apply synthetic italic to the regular face, NOT fall back to a different
+  -- family from prefs.
+  -->
+<div>العربي <span>العربي</span> العربي</div>
+</body>
+</html>
diff --git a/layout/reftests/font-matching/arial-arabic.html b/layout/reftests/font-matching/arial-arabic.html
new file mode 100644
index 000000000000..5f363ca261db
--- /dev/null
+++ b/layout/reftests/font-matching/arial-arabic.html
@@ -0,0 +1,26 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>Bug 769475 - test for italicized Arabic script in Arial</title>
+<style type="text/css">
+body {
+  font-family: arial, serif;
+  font-size: 36px;
+  line-height: 72px;
+}
+span {
+  font-style: italic;
+  color: white;
+}
+</style>
+</head>
+<body lang="ar">
+<!-- the white span should have the same width whether it's italicized or not,
+  -- as Arial does not have Arabic characters in the italic face but we should
+  -- apply synthetic italic to the regular face, NOT fall back to a different
+  -- family from prefs.
+  -->
+<div>العربي <span>العربي</span> العربي</div>
+</body>
+</html>
diff --git a/layout/reftests/font-matching/reftest.list b/layout/reftests/font-matching/reftest.list
index 5d45d1c81904..72735cef1966 100644
--- a/layout/reftests/font-matching/reftest.list
+++ b/layout/reftests/font-matching/reftest.list
@@ -81,3 +81,7 @@ HTTP(..) == font-stretch-1.html font-stretch-1-ref.html
 random-if(!(cocoaWidget||/^Windows\x20NT\x206\.1/.test(http.oscpu))) skip-if(gtk2Widget) != bold-system-fallback-1.html bold-system-fallback-1-notref.html
 # test 2 uses Chess symbols; expected to pass on Android
 random-if(!Android) skip-if(gtk2Widget) != bold-system-fallback-2.html bold-system-fallback-2-notref.html
+
+# Bug 769475 - applying 'italic' to Arabic text in Arial should NOT change family or metrics.
+# Expected to pass on MacOSX and Windows; other platforms unknown, depending on font availability.
+random-if(!(cocoaWidget||winWidget)) == arial-arabic.html arial-arabic-ref.html
