diff --git a/changelog.d/oauth-app.fix b/changelog.d/oauth-app.fix
new file mode 100644
index 000000000..eb917462f
--- /dev/null
+++ b/changelog.d/oauth-app.fix
@@ -0,0 +1 @@
+Prevent OAuth App flow from creating duplicate entries
diff --git a/lib/pleroma/web/mastodon_api/controllers/app_controller.ex b/lib/pleroma/web/mastodon_api/controllers/app_controller.ex
index 844673ae0..e5e8ea8f5 100644
--- a/lib/pleroma/web/mastodon_api/controllers/app_controller.ex
+++ b/lib/pleroma/web/mastodon_api/controllers/app_controller.ex
@@ -33,11 +33,9 @@ defmodule Pleroma.Web.MastodonAPI.AppController do
     app_attrs =
       params
       |> Map.take([:client_name, :redirect_uris, :website])
-      |> Map.put(:scopes, scopes)
       |> Maps.put_if_present(:user_id, user_id)
 
-    with cs <- App.register_changeset(%App{}, app_attrs),
-         {:ok, app} <- Repo.insert(cs) do
+    with {:ok, app} <- App.get_or_make(app_attrs, scopes) do
       render(conn, "show.json", app: app)
     end
   end
diff --git a/test/pleroma/web/mastodon_api/controllers/app_controller_test.exs b/test/pleroma/web/mastodon_api/controllers/app_controller_test.exs
index bc9d4048c..1e2e68791 100644
--- a/test/pleroma/web/mastodon_api/controllers/app_controller_test.exs
+++ b/test/pleroma/web/mastodon_api/controllers/app_controller_test.exs
@@ -89,4 +89,51 @@ defmodule Pleroma.Web.MastodonAPI.AppControllerTest do
     assert expected == json_response_and_validate_schema(conn, 200)
     assert app.user_id == user.id
   end
+
+  test "creates an oauth app without a user", %{conn: conn} do
+    app_attrs = build(:oauth_app)
+
+    conn =
+      conn
+      |> put_req_header("content-type", "application/json")
+      |> post("/api/v1/apps", %{
+        client_name: app_attrs.client_name,
+        redirect_uris: app_attrs.redirect_uris
+      })
+
+    [app] = Repo.all(App)
+
+    expected = %{
+      "name" => app.client_name,
+      "website" => app.website,
+      "client_id" => app.client_id,
+      "client_secret" => app.client_secret,
+      "id" => app.id |> to_string(),
+      "redirect_uri" => app.redirect_uris,
+      "vapid_key" => Push.vapid_config() |> Keyword.get(:public_key)
+    }
+
+    assert expected == json_response_and_validate_schema(conn, 200)
+  end
+
+  test "does not duplicate apps with the same client name", %{conn: conn} do
+    client_name = "BleromaSE"
+    redirect_uris = "https://bleroma.app/oauth-callback"
+
+    for _i <- 1..3 do
+      conn
+      |> put_req_header("content-type", "application/json")
+      |> post("/api/v1/apps", %{
+        client_name: client_name,
+        redirect_uris: redirect_uris
+      })
+      |> json_response_and_validate_schema(200)
+    end
+
+    apps = Repo.all(App)
+
+    assert length(apps) == 1
+    assert List.first(apps).client_name == client_name
+    assert List.first(apps).redirect_uris == redirect_uris
+  end
 end