diff --git a/lib/plug/rewrite_on.ex b/lib/plug/rewrite_on.ex
index f2b20533..62fdd035 100644
--- a/lib/plug/rewrite_on.ex
+++ b/lib/plug/rewrite_on.ex
@@ -96,6 +96,9 @@ defmodule Plug.RewriteOn do
   defp put_scheme(%{scheme: :http, port: 80} = conn, ["https"]),
     do: %{conn | scheme: :https, port: 443}
 
+  defp put_scheme(%{scheme: :http, port: 80} = conn, ["wss"]),
+    do: %{conn | scheme: :https, port: 443}
+
   defp put_scheme(conn, ["https"]),
     do: %{conn | scheme: :https}
 
diff --git a/test/plug/rewrite_on_test.exs b/test/plug/rewrite_on_test.exs
index 5dafedad..c0c29c34 100644
--- a/test/plug/rewrite_on_test.exs
+++ b/test/plug/rewrite_on_test.exs
@@ -37,6 +37,16 @@ defmodule Plug.RewriteOnTest do
     assert conn.port == 443
   end
 
+  test "rewrites http to https when x-forwarded-proto value wss" do
+    conn =
+      conn(:get, "http://example.com/")
+      |> put_req_header("x-forwarded-proto", "wss")
+      |> call(:x_forwarded_proto)
+
+    assert conn.scheme == :https
+    assert conn.port == 443
+  end
+
   test "doesn't change the port when it doesn't match the scheme" do
     conn =
       conn(:get, "http://example.com:1234/")