diff --git a/.github/workflows/check-cpp23.yml b/.github/workflows/check-cpp23.yml
index 5022b44e0a..2cd53f2208 100644
--- a/.github/workflows/check-cpp23.yml
+++ b/.github/workflows/check-cpp23.yml
@@ -14,6 +14,7 @@ on:
 jobs:
   build:
     name: Build with C++23 support enabled
+    if: ${{ github.repository == 'lammps/lammps' }}
     runs-on: ubuntu-latest
     env:
       CCACHE_DIR: ${{ github.workspace }}/.ccache
diff --git a/.github/workflows/check-vla.yml b/.github/workflows/check-vla.yml
index af1e269333..ab89018a3d 100644
--- a/.github/workflows/check-vla.yml
+++ b/.github/workflows/check-vla.yml
@@ -14,6 +14,7 @@ on:
 jobs:
   build:
     name: Build with -Werror=vla
+    if: ${{ github.repository == 'lammps/lammps' }}
     runs-on: ubuntu-latest
     env:
       CCACHE_DIR: ${{ github.workspace }}/.ccache
diff --git a/.github/workflows/codeql-analysis.yml b/.github/workflows/codeql-analysis.yml
index 47fdae311f..c7dd945f5f 100644
--- a/.github/workflows/codeql-analysis.yml
+++ b/.github/workflows/codeql-analysis.yml
@@ -10,6 +10,7 @@ on:
 jobs:
   analyze:
     name: Analyze
+    if: ${{ github.repository == 'lammps/lammps' }}
     runs-on: ubuntu-latest
 
     permissions:
diff --git a/.github/workflows/compile-msvc.yml b/.github/workflows/compile-msvc.yml
index 4f04979925..7560bc0549 100644
--- a/.github/workflows/compile-msvc.yml
+++ b/.github/workflows/compile-msvc.yml
@@ -18,6 +18,7 @@ concurrency:
 jobs:
   build:
     name: Windows Compilation Test
+    if: ${{ github.repository == 'lammps/lammps' }}
     runs-on: windows-latest
     env:
       CCACHE_DIR: ${{ github.workspace }}/.ccache
diff --git a/.github/workflows/coverity.yml b/.github/workflows/coverity.yml
index 7e38643b4c..c0c3e3f89a 100644
--- a/.github/workflows/coverity.yml
+++ b/.github/workflows/coverity.yml
@@ -9,6 +9,7 @@ on:
 jobs:
   analyze:
     name: Analyze
+    if: ${{ github.repository == 'lammps/lammps' }}
     runs-on: ubuntu-latest
     container:
       image: lammps/buildenv:ubuntu20.04
diff --git a/.github/workflows/full-regression.yml b/.github/workflows/full-regression.yml
index 683f65409d..a6b5353b9b 100644
--- a/.github/workflows/full-regression.yml
+++ b/.github/workflows/full-regression.yml
@@ -12,6 +12,7 @@ jobs:
   build:
     name: Build LAMMPS
     # restrict to official LAMMPS repository
+    if: ${{ github.repository == 'lammps/lammps' }}
     runs-on: ubuntu-latest
     env:
       CCACHE_DIR: ${{ github.workspace }}/.ccache
diff --git a/.github/workflows/kokkos-regression.yaml b/.github/workflows/kokkos-regression.yaml
index b3e685806b..a475c1eb7b 100644
--- a/.github/workflows/kokkos-regression.yaml
+++ b/.github/workflows/kokkos-regression.yaml
@@ -12,6 +12,7 @@ jobs:
   build:
     name: Build LAMMPS with Kokkos OpenMP
     # restrict to official LAMMPS repository
+    if: ${{ github.repository == 'lammps/lammps' }}
     runs-on: ubuntu-latest
     env:
       CCACHE_DIR: ${{ github.workspace }}/.ccache
diff --git a/.github/workflows/quick-regression.yml b/.github/workflows/quick-regression.yml
index 5325e4b6cb..88794bfa0a 100644
--- a/.github/workflows/quick-regression.yml
+++ b/.github/workflows/quick-regression.yml
@@ -16,6 +16,7 @@ jobs:
   build:
     name: Build LAMMPS
     # restrict to official LAMMPS repository
+    if: ${{ github.repository == 'lammps/lammps' }}
     runs-on: ubuntu-latest
     env:
       CCACHE_DIR: ${{ github.workspace }}/.ccache
diff --git a/.github/workflows/style-check.yml b/.github/workflows/style-check.yml
index e97163269c..7be2c4fc46 100644
--- a/.github/workflows/style-check.yml
+++ b/.github/workflows/style-check.yml
@@ -18,6 +18,7 @@ concurrency:
 jobs:
   build:
     name: Programming Style Conformance
+    if: ${{ github.repository == 'lammps/lammps' }}
     runs-on: ubuntu-latest
 
     steps:
diff --git a/.github/workflows/unittest-linux.yml b/.github/workflows/unittest-linux.yml
index 04b1d1f328..ce98fcea35 100644
--- a/.github/workflows/unittest-linux.yml
+++ b/.github/workflows/unittest-linux.yml
@@ -18,6 +18,7 @@ concurrency:
 jobs:
   build:
     name: Linux Unit Test
+    if: ${{ github.repository == 'lammps/lammps' }}
     runs-on: ubuntu-latest
     env:
       CCACHE_DIR: ${{ github.workspace }}/.ccache
diff --git a/.github/workflows/unittest-macos.yml b/.github/workflows/unittest-macos.yml
index d3e242774c..0d478a9d6b 100644
--- a/.github/workflows/unittest-macos.yml
+++ b/.github/workflows/unittest-macos.yml
@@ -18,6 +18,7 @@ concurrency:
 jobs:
   build:
     name: MacOS Unit Test
+    if: ${{ github.repository == 'lammps/lammps' }}
     runs-on: macos-13
     env:
       CCACHE_DIR: ${{ github.workspace }}/.ccache