diff --git a/lib/hexdocs/store/gs.ex b/lib/hexdocs/store/gs.ex
index d041310..78cc230 100644
--- a/lib/hexdocs/store/gs.ex
+++ b/lib/hexdocs/store/gs.ex
@@ -86,19 +86,21 @@ defmodule Hexdocs.Store.GS do
     |> Task.async_stream(
       &delete(bucket, &1),
       max_concurrency: 10,
-      timeout: 10_000
+      timeout: 60_000
     )
     |> Hexdocs.Utils.raise_async_stream_error()
     |> Stream.run()
   end
 
+  # 404 means the object was already deleted, for example by a concurrent
+  # upload of the same package deleting the same unversioned files
   defp delete(bucket, key) do
     url = url(bucket, key)
 
-    {:ok, 204, _headers, _body} =
-      Hexdocs.HTTP.retry("gs", url, fn -> Hexdocs.HTTP.delete(url, headers()) end)
-
-    :ok
+    case Hexdocs.HTTP.retry("gs", url, fn -> Hexdocs.HTTP.delete(url, headers()) end) do
+      {:ok, status, _headers, _body} when status in [204, 404] ->
+        :ok
+    end
   end
 
   defp list_stream(bucket, prefix) do
diff --git a/test/hexdocs/store/gs_test.exs b/test/hexdocs/store/gs_test.exs
new file mode 100644
index 0000000..db681c2
--- /dev/null
+++ b/test/hexdocs/store/gs_test.exs
@@ -0,0 +1,105 @@
+defmodule Hexdocs.Store.GSTest do
+  use ExUnit.Case, async: false
+
+  def fake_gs_auth, do: [{"authorization", "Bearer fake-token"}]
+
+  defmodule MockGCSPlug do
+    import Plug.Conn
+
+    def init(opts), do: opts
+
+    def call(conn, _opts) do
+      case {conn.method, conn.path_info} do
+        {"DELETE", ["hexdocs-test" | rest]} ->
+          delete_file(conn, decode_path(rest))
+
+        _ ->
+          send_resp(conn, 404, "Not Found")
+      end
+    end
+
+    defp decode_path(segments) do
+      segments
+      |> Enum.map(&URI.decode/1)
+      |> Enum.join("/")
+    end
+
+    defp delete_file(conn, path) do
+      case :ets.lookup(:mock_gs_store_files, path) do
+        [{^path, _content}] ->
+          :ets.delete(:mock_gs_store_files, path)
+          send_resp(conn, 204, "")
+
+        [] ->
+          body =
+            "<?xml version='1.0' encoding='UTF-8'?>" <>
+              "<Error><Code>NoSuchKey</Code><Message>The specified key does not exist.</Message></Error>"
+
+          conn
+          |> put_resp_content_type("application/xml")
+          |> send_resp(404, body)
+      end
+    end
+  end
+
+  setup do
+    if :ets.whereis(:mock_gs_store_files) == :undefined do
+      :ets.new(:mock_gs_store_files, [:named_table, :public, :set])
+    end
+
+    :ets.delete_all_objects(:mock_gs_store_files)
+
+    pid = start_supervised!({Bandit, plug: MockGCSPlug, scheme: :http, port: 0})
+    {:ok, {_, port}} = ThousandIsland.listener_info(pid)
+
+    original_gs_url = Application.get_env(:hexdocs, :gs_url)
+    original_gs_auth = Application.get_env(:hexdocs, :gs_auth)
+
+    Application.put_env(:hexdocs, :gs_url, "http://localhost:#{port}")
+    Application.put_env(:hexdocs, :gs_auth, {__MODULE__, :fake_gs_auth})
+
+    on_exit(fn ->
+      if original_gs_url do
+        Application.put_env(:hexdocs, :gs_url, original_gs_url)
+      else
+        Application.delete_env(:hexdocs, :gs_url)
+      end
+
+      if original_gs_auth do
+        Application.put_env(:hexdocs, :gs_auth, original_gs_auth)
+      else
+        Application.delete_env(:hexdocs, :gs_auth)
+      end
+    end)
+
+    :ok
+  end
+
+  describe "delete_many/2" do
+    test "deletes existing keys" do
+      :ets.insert(:mock_gs_store_files, {"package/1.0.0/index.html", "contents"})
+      :ets.insert(:mock_gs_store_files, {"package/docs_config.js", "contents"})
+
+      assert :ok =
+               Hexdocs.Store.GS.delete_many("hexdocs-test", [
+                 "package/1.0.0/index.html",
+                 "package/docs_config.js"
+               ])
+
+      assert :ets.lookup(:mock_gs_store_files, "package/1.0.0/index.html") == []
+      assert :ets.lookup(:mock_gs_store_files, "package/docs_config.js") == []
+    end
+
+    test "tolerates keys that are already deleted" do
+      :ets.insert(:mock_gs_store_files, {"package/1.0.0/index.html", "contents"})
+
+      assert :ok =
+               Hexdocs.Store.GS.delete_many("hexdocs-test", [
+                 "package/1.0.0/index.html",
+                 "package/docs_config.js"
+               ])
+
+      assert :ets.lookup(:mock_gs_store_files, "package/1.0.0/index.html") == []
+    end
+  end
+end