diff --git a/lib/graphql_ws_client/drivers/gun.ex b/lib/graphql_ws_client/drivers/gun.ex
index edb2197..13f9287 100644
--- a/lib/graphql_ws_client/drivers/gun.ex
+++ b/lib/graphql_ws_client/drivers/gun.ex
@@ -79,7 +79,15 @@ defmodule GraphQLWSClient.Drivers.Gun do
     with {:await_up, {:ok, _protocol}} <-
            {:await_up,
             opts.adapter.await_up(pid, opts.connect_options.connect_timeout)},
-         stream_ref = opts.adapter.ws_upgrade(pid, config.path),
+         stream_ref =
+           opts.adapter.ws_upgrade(
+             pid,
+             config.path,
+             [{"sec-websocket-protocol", opts.subprotocol}],
+             %{
+               protocols: [{opts.subprotocol, :gun_ws_h}]
+             }
+           ),
          :ok <- await_upgrade(opts.upgrade_timeout),
          :ok <-
            init_connection(
diff --git a/lib/graphql_ws_client/drivers/gun/opts.ex b/lib/graphql_ws_client/drivers/gun/opts.ex
index c7836c4..7c0cdf1 100644
--- a/lib/graphql_ws_client/drivers/gun/opts.ex
+++ b/lib/graphql_ws_client/drivers/gun/opts.ex
@@ -10,6 +10,7 @@ defmodule GraphQLWSClient.Drivers.Gun.Opts do
             adapter: :gun,
             connect_options: @default_connect_options,
             json_library: Jason,
+            subprotocol: "graphql-transport-ws",
             upgrade_timeout: :timer.seconds(5)
 
   @type t :: %__MODULE__{
@@ -17,6 +18,7 @@ defmodule GraphQLWSClient.Drivers.Gun.Opts do
           adapter: module,
           connect_options: %{optional(atom) => any},
           json_library: module,
+          subprotocol: String.t(),
           upgrade_timeout: timeout
         }
 
diff --git a/test/graphql_ws_client/drivers/gun_test.exs b/test/graphql_ws_client/drivers/gun_test.exs
index 61ff500..9241d48 100644
--- a/test/graphql_ws_client/drivers/gun_test.exs
+++ b/test/graphql_ws_client/drivers/gun_test.exs
@@ -65,7 +65,17 @@ defmodule GraphQLWSClient.Drivers.GunTest do
       |> expect(:await_up, fn ^pid, 250 ->
         {:ok, :http}
       end)
-      |> expect(:ws_upgrade, fn ^pid, "/subscriptions" ->
+      |> expect(:ws_upgrade, fn ^pid,
+                                "/subscriptions",
+                                [
+                                  {"sec-websocket-protocol",
+                                   "graphql-transport-ws"}
+                                ],
+                                %{
+                                  protocols: [
+                                    {"graphql-transport-ws", :gun_ws_h}
+                                  ]
+                                } ->
         send(self(), {:gun_upgrade, pid, stream_ref, ["websocket"], nil})
         stream_ref
       end)
@@ -118,7 +128,7 @@ defmodule GraphQLWSClient.Drivers.GunTest do
       WSClientMock
       |> expect(:open, fn _, _, _ -> {:ok, pid} end)
       |> expect(:await_up, fn _, _ -> {:ok, :http} end)
-      |> expect(:ws_upgrade, fn _, _ -> stream_ref end)
+      |> expect(:ws_upgrade, fn _, _, _, _ -> stream_ref end)
       |> expect(:close, fn ^pid -> :ok end)
 
       assert Gun.connect(@conn) == {:error, %SocketError{cause: :timeout}}
@@ -133,7 +143,7 @@ defmodule GraphQLWSClient.Drivers.GunTest do
       WSClientMock
       |> expect(:open, fn _, _, _ -> {:ok, pid} end)
       |> expect(:await_up, fn _, _ -> {:ok, :http} end)
-      |> expect(:ws_upgrade, fn _, _ ->
+      |> expect(:ws_upgrade, fn _, _, _, _ ->
         send(self(), {:gun_response, pid, stream_ref, nil, code, nil})
         stream_ref
       end)
@@ -153,7 +163,7 @@ defmodule GraphQLWSClient.Drivers.GunTest do
       WSClientMock
       |> expect(:open, fn _, _, _ -> {:ok, pid} end)
       |> expect(:await_up, fn _, _ -> {:ok, :http} end)
-      |> expect(:ws_upgrade, fn _, _ ->
+      |> expect(:ws_upgrade, fn _, _, _, _ ->
         send(self(), {:gun_error, pid, stream_ref, reason})
         stream_ref
       end)
@@ -171,7 +181,7 @@ defmodule GraphQLWSClient.Drivers.GunTest do
       WSClientMock
       |> expect(:open, fn _, _, _ -> {:ok, pid} end)
       |> expect(:await_up, fn _, _ -> {:ok, :http} end)
-      |> expect(:ws_upgrade, fn _, _ ->
+      |> expect(:ws_upgrade, fn _, _, _, _ ->
         send(self(), {:gun_upgrade, pid, stream_ref, ["websocket"], nil})
         stream_ref
       end)
@@ -188,7 +198,7 @@ defmodule GraphQLWSClient.Drivers.GunTest do
       WSClientMock
       |> expect(:open, fn _, _, _ -> {:ok, pid} end)
       |> expect(:await_up, fn _, _ -> {:ok, :http} end)
-      |> expect(:ws_upgrade, fn _, _ ->
+      |> expect(:ws_upgrade, fn _, _, _, _ ->
         send(self(), {:gun_upgrade, pid, stream_ref, ["websocket"], nil})
         stream_ref
       end)
@@ -209,7 +219,7 @@ defmodule GraphQLWSClient.Drivers.GunTest do
       WSClientMock
       |> expect(:open, fn _, _, _ -> {:ok, pid} end)
       |> expect(:await_up, fn _, _ -> {:ok, :http} end)
-      |> expect(:ws_upgrade, fn _, _ ->
+      |> expect(:ws_upgrade, fn _, _, _, _ ->
         send(self(), {:gun_upgrade, pid, stream_ref, ["websocket"], nil})
         stream_ref
       end)
@@ -227,7 +237,7 @@ defmodule GraphQLWSClient.Drivers.GunTest do
       WSClientMock
       |> expect(:open, fn _, _, _ -> {:ok, pid} end)
       |> expect(:await_up, fn _, _ -> {:ok, :http} end)
-      |> expect(:ws_upgrade, fn _, _ ->
+      |> expect(:ws_upgrade, fn _, _, _, _ ->
         send(self(), {:gun_upgrade, pid, stream_ref, ["websocket"], nil})
         stream_ref
       end)
@@ -253,7 +263,7 @@ defmodule GraphQLWSClient.Drivers.GunTest do
       WSClientMock
       |> expect(:open, fn _, _, _ -> {:ok, pid} end)
       |> expect(:await_up, fn _, _ -> {:ok, :http} end)
-      |> expect(:ws_upgrade, fn _, _ ->
+      |> expect(:ws_upgrade, fn _, _, _, _ ->
         send(self(), {:gun_upgrade, pid, stream_ref, ["websocket"], nil})
         stream_ref
       end)
diff --git a/test/support/ws_client.ex b/test/support/ws_client.ex
index bb8afbc..9dcbcbc 100644
--- a/test/support/ws_client.ex
+++ b/test/support/ws_client.ex
@@ -10,7 +10,8 @@ defmodule GraphQLWSClient.WSClient do
   @callback await_up(pid, timeout) ::
               {:ok, :http | :http2 | :raw | :socks} | {:error, any}
 
-  @callback ws_upgrade(pid, binary) :: reference
+  @callback ws_upgrade(pid, binary, :gun.req_headers(), :gun.ws_opts()) ::
+              reference
 
   @callback ws_send(pid, reference, frame :: term) :: :ok