diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 2541f5b0..45febdb6 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -3467,6 +3467,7 @@ XML:
   - .jelly
   - .kml
   - .launch
+  - .mdpolicy
   - .mm
   - .mxml
   - .nproj
diff --git a/samples/XML/Example.mdpolicy b/samples/XML/Example.mdpolicy
new file mode 100644
index 00000000..6c9ff048
--- /dev/null
+++ b/samples/XML/Example.mdpolicy
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<PolicySet name="Example.mdpolicy">
+  <TextStylePolicy inheritsSet="VisualStudio" inheritsScope="text/plain" scope="text/x-csharp">
+    <FileWidth>120</FileWidth>
+    <TabsToSpaces>False</TabsToSpaces>
+    <NoTabsAfterNonTabs>True</NoTabsAfterNonTabs>
+  </TextStylePolicy>
+  <DotNetNamingPolicy>
+    <DirectoryNamespaceAssociation>None</DirectoryNamespaceAssociation>
+    <ResourceNamePolicy>FileFormatDefault</ResourceNamePolicy>
+  </DotNetNamingPolicy>
+</PolicySet>
\ No newline at end of file