diff --git a/plugins/collapseGroups.js b/plugins/collapseGroups.js
index 2626ce85..b572f6a9 100644
--- a/plugins/collapseGroups.js
+++ b/plugins/collapseGroups.js
@@ -52,7 +52,7 @@ exports.fn = function(item) {
                     var inner = g.content[0];
 
                     if (inner.isElem() && !inner.hasAttr('id') && (
-                        !g.hasAttr('clip-path') ||
+                        !g.hasAttr('clip-path') && !g.hasAttr('mask') ||
                         inner.isElem('g') && !g.hasAttr('transform') && !inner.hasAttr('transform')
                     )) {
                         g.eachAttr(function(attr) {
diff --git a/test/plugins/collapseGroups.10.svg b/test/plugins/collapseGroups.10.svg
index fe59581d..aa05c576 100644
--- a/test/plugins/collapseGroups.10.svg
+++ b/test/plugins/collapseGroups.10.svg
@@ -2,9 +2,13 @@
     <clipPath id="a">
        <path d="..."/>
     </clipPath>
+    <path d="..."/>
     <g clip-path="url(#a)">
         <path d="..." transform="scale(.2)"/>
     </g>
+    <g mask="url(#a)">
+        <path d="..." transform="scale(.2)"/>
+    </g>
 </svg>
 
 @@@
@@ -13,7 +17,11 @@
     <clipPath id="a">
         <path d="..."/>
     </clipPath>
+    <path d="..."/>
     <g clip-path="url(#a)">
         <path d="..." transform="scale(.2)"/>
     </g>
+    <g mask="url(#a)">
+        <path d="..." transform="scale(.2)"/>
+    </g>
 </svg>