diff --git a/layout/reftests/svg/opacity-and-pattern-01.svg b/layout/reftests/svg/opacity-and-pattern-01.svg
new file mode 100644
index 00000000000..6e799f56d4e
--- /dev/null
+++ b/layout/reftests/svg/opacity-and-pattern-01.svg
@@ -0,0 +1,32 @@
+<svg xmlns="http://www.w3.org/2000/svg" version="1.1">
+
+  <title>Testcase for opacity on elements referencing a pattern</title>
+
+  <!-- From https://bugzilla.mozilla.org/show_bug.cgi?id=374280 -->
+
+  <defs>
+    <pattern id="lime" width="100%" height="100%" patternUnits="userSpaceOnUse">
+      <rect width="100%" height="100%" fill="lime"/>
+    </pattern>
+
+    <pattern id="red" width="100%" height="100%" patternUnits="userSpaceOnUse">
+      <rect width="100%" height="100%" fill="red"/>
+    </pattern>
+  </defs>
+
+  <rect width="100%" height="100%" fill="red"/>
+
+  <!-- Create the "pass" rect using a pattern so the testcase doesn't seem to
+       pass if patterns are not supported -->
+  <rect width="100%" height="100%" fill="url(#lime)"/>
+
+  <!-- test 'opacity' -->
+  <rect width="25%" height="100%" fill="url(#red)" opacity="0"/>
+
+  <!-- test 'fill-opacity' -->
+  <rect x="25%" width="25%" height="100%" fill="url(#red)" fill-opacity="0"/>
+
+  <!-- test 'stroke-opacity' -->
+  <line x1="75%" x2="75%" y2="100%" stroke="url(#red)" stroke-width="50%" stroke-opacity="0"/>
+
+</svg>
diff --git a/layout/reftests/svg/reftest.list b/layout/reftests/svg/reftest.list
index 15535ae0728..bda498b7a3c 100755
--- a/layout/reftests/svg/reftest.list
+++ b/layout/reftests/svg/reftest.list
@@ -4,6 +4,7 @@
 == getElementById-a-element-01.svg pass.svg
 == nested-viewBox-01.svg pass.svg
 == opacity-and-gradient-01.svg pass.svg
+== opacity-and-pattern-01.svg pass.svg
 == pseudo-classes-01.svg pass.svg
 == pseudo-classes-02.svg pseudo-classes-02-ref.svg
 == rect-with-rx-or-ry-01.svg rect-with-rx-or-ry-01-ref.svg