diff --git a/data/prefixes.js b/data/prefixes.js
index e4e26b5d0..073a78c93 100644
--- a/data/prefixes.js
+++ b/data/prefixes.js
@@ -750,6 +750,8 @@ f(prefixCssMasks, browsers => {
     [
       'mask',
       'mask-position',
+      'mask-position-x',
+      'mask-position-y',
       'mask-size',
       'mask-border',
       'mask-border-outset',
diff --git a/test/autoprefixer.test.js b/test/autoprefixer.test.js
index 658b1aafc..4da9fd6c3 100644
--- a/test/autoprefixer.test.js
+++ b/test/autoprefixer.test.js
@@ -817,6 +817,10 @@ test('supports mask-composite', () => {
   check('mask-composite')
 })
 
+test('supports mask-position-x and mask-position-y', () => {
+  check('mask-position')
+})
+
 test('supports image-set()', () => {
   check('image-set')
 })
diff --git a/test/cases/mask-position.css b/test/cases/mask-position.css
new file mode 100644
index 000000000..c0415a511
--- /dev/null
+++ b/test/cases/mask-position.css
@@ -0,0 +1,5 @@
+a {
+  mask-position: center;
+  mask-position-x: 10px;
+  mask-position-y: 20px;
+}
diff --git a/test/cases/mask-position.out.css b/test/cases/mask-position.out.css
new file mode 100644
index 000000000..7942add0d
--- /dev/null
+++ b/test/cases/mask-position.out.css
@@ -0,0 +1,8 @@
+a {
+  -webkit-mask-position: center;
+          mask-position: center;
+  -webkit-mask-position-x: 10px;
+          mask-position-x: 10px;
+  -webkit-mask-position-y: 20px;
+          mask-position-y: 20px;
+}