diff --git a/lib/ex_doc/formatter/html/search_data.ex b/lib/ex_doc/formatter/html/search_data.ex
index 5ec0e4edd..10b76e1ef 100644
--- a/lib/ex_doc/formatter/html/search_data.ex
+++ b/lib/ex_doc/formatter/html/search_data.ex
@@ -2,12 +2,13 @@ defmodule ExDoc.Formatter.HTML.SearchData do
   @moduledoc false
   alias ExDoc.Utils
 
-  def create(nodes, extras, _proglang) do
+  def create(nodes, extras, proglang) do
     items = Enum.flat_map(nodes, &module/1) ++ Enum.flat_map(extras, &extra/1)
 
     data = %{
       items: items,
       content_type: "text/markdown",
+      proglang: proglang,
       producer: %{
         name: "ex_doc",
         version: to_string(Application.spec(:ex_doc)[:vsn])
diff --git a/test/ex_doc/formatter/html/search_data_test.exs b/test/ex_doc/formatter/html/search_data_test.exs
index 3e1484866..e8f2fdeed 100644
--- a/test/ex_doc/formatter/html/search_data_test.exs
+++ b/test/ex_doc/formatter/html/search_data_test.exs
@@ -25,6 +25,7 @@ defmodule ExDoc.Formatter.HTML.SearchDataTest do
     config = %ExDoc.Config{output: "#{c.tmp_dir}/doc"}
     data = search_data(modules, config)
     assert data["content_type"] == "text/markdown"
+    assert data["proglang"] == "elixir"
     assert data["producer"]["name"] == "ex_doc"
     [item1, item2] = data["items"]