diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 46625f3c..9cc5a882 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -824,6 +824,8 @@ Elixir:
   - .ex
   - .exs
   ace_mode: elixir
+  filenames:
+  - mix.lock
 
 Elm:
   type: programming
diff --git a/samples/Elixir/filenames/mix.lock b/samples/Elixir/filenames/mix.lock
new file mode 100644
index 00000000..830b074c
--- /dev/null
+++ b/samples/Elixir/filenames/mix.lock
@@ -0,0 +1,10 @@
+%{"cowboy": {:hex, :cowboy, "1.0.0"},
+  "cowlib": {:hex, :cowlib, "1.0.1"},
+  "hackney": {:hex, :hackney, "0.14.3"},
+  "hound": {:hex, :hound, "0.6.0"},
+  "httpoison": {:hex, :httpoison, "0.5.0"},
+  "idna": {:hex, :idna, "1.0.1"},
+  "phoenix": {:hex, :phoenix, "0.10.0"},
+  "plug": {:hex, :plug, "0.11.1"},
+  "poison": {:hex, :poison, "1.3.1"},
+  "ranch": {:hex, :ranch, "1.0.0"}}