diff --git a/.github/workflows/manual-nixos.yml b/.github/workflows/manual-nixos.yml
index c885f6f7665..032a456569d 100644
--- a/.github/workflows/manual-nixos.yml
+++ b/.github/workflows/manual-nixos.yml
@@ -12,6 +12,7 @@ on:
 jobs:
   nixos:
     runs-on: ubuntu-latest
+    if: github.repository_owner == 'NixOS'
     steps:
       - uses: actions/checkout@v2
         with:
diff --git a/.github/workflows/manual-nixpkgs.yml b/.github/workflows/manual-nixpkgs.yml
index 6f7ad10efd9..77655c494e0 100644
--- a/.github/workflows/manual-nixpkgs.yml
+++ b/.github/workflows/manual-nixpkgs.yml
@@ -12,6 +12,7 @@ on:
 jobs:
   nixpkgs:
     runs-on: ubuntu-latest
+    if: github.repository_owner == 'NixOS'
     steps:
       - uses: actions/checkout@v2
         with: