diff --git a/lib/plug/static.ex b/lib/plug/static.ex
index c5aad8b5..fd9804ba 100644
--- a/lib/plug/static.ex
+++ b/lib/plug/static.ex
@@ -163,7 +163,7 @@ defmodule Plug.Static do
     %{
       encodings: encodings,
       only_rules: {Keyword.get(opts, :only, []), Keyword.get(opts, :only_matching, [])},
-      qs_cache: Keyword.get(opts, :cache_control_for_vsn_requests, "public, max-age=31536000"),
+      qs_cache: Keyword.get(opts, :cache_control_for_vsn_requests, "public, max-age=31536000, immutable"),
       et_cache: Keyword.get(opts, :cache_control_for_etags, "public"),
       et_generation: Keyword.get(opts, :etag_generation, nil),
       headers: Keyword.get(opts, :headers, %{}),
diff --git a/test/plug/static_test.exs b/test/plug/static_test.exs
index d3f65b14..2a3ed8cb 100644
--- a/test/plug/static_test.exs
+++ b/test/plug/static_test.exs
@@ -148,7 +148,7 @@ defmodule Plug.StaticTest do
     assert conn.status == 200
     assert conn.resp_body == "HELLO"
     assert get_resp_header(conn, "content-type") == ["text/plain"]
-    assert get_resp_header(conn, "cache-control") == ["public, max-age=31536000"]
+    assert get_resp_header(conn, "cache-control") == ["public, max-age=31536000, immutable"]
     assert get_resp_header(conn, "etag") == []
     assert get_resp_header(conn, "x-custom") == ["x-value"]
   end
@@ -503,7 +503,7 @@ defmodule Plug.StaticTest do
       assert get_resp_header(conn, "content-type") == ["text/plain"]
       assert get_resp_header(conn, "accept-ranges") == ["bytes"]
       assert get_resp_header(conn, "content-range") == ["bytes 0-1/5"]
-      assert get_resp_header(conn, "cache-control") == ["public, max-age=31536000"]
+      assert get_resp_header(conn, "cache-control") == ["public, max-age=31536000, immutable"]
       assert get_resp_header(conn, "etag") == []
       assert get_resp_header(conn, "x-custom") == ["x-value"]
     end