diff --git a/.travis.yml b/.travis.yml
index 144ac06..7ab7b15 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -19,7 +19,7 @@ notifications:
 script: sh build-package.sh
 
 env:
-    - APM_TEST_PACKAGES="language-marko language-html-swig language-svg"
+    - APM_TEST_PACKAGES="language-marko language-html-swig language-svg language-d"
 
 cache:
     - pip: true
diff --git a/src/languages/d.coffee b/src/languages/d.coffee
index 0e89e3d..9215c3f 100644
--- a/src/languages/d.coffee
+++ b/src/languages/d.coffee
@@ -14,6 +14,7 @@ module.exports = {
   Supported extensions
   ###
   extensions: [
+    "d"
   ]
 
   defaultBeautifier: "dfmt"