diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 19748bb87..90256ce12 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,7 +20,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-24.04, macos-latest]
+        os: [ubuntu-24.04, macos-14]
     runs-on: ${{ matrix.os }}
     timeout-minutes: 60
     steps:
@@ -51,7 +51,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-24.04, macos-latest]
+        os: [ubuntu-24.04, macos-14]
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v4
@@ -70,7 +70,7 @@ jobs:
     - run: sudo apt install fish zsh
       if: matrix.os == 'ubuntu-24.04'
     - run: brew install fish
-      if: matrix.os == 'macos-latest'
+      if: matrix.os == 'macos-14'
     - run: exec bash -c "nix-instantiate -E 'builtins.currentTime' --eval"
     - run: exec sh -c "nix-instantiate -E 'builtins.currentTime' --eval"
     - run: exec zsh -c "nix-instantiate -E 'builtins.currentTime' --eval"
diff --git a/.mergify.yml b/.mergify.yml
index ce95d4382..9749583df 100644
--- a/.mergify.yml
+++ b/.mergify.yml
@@ -5,9 +5,9 @@ queue_rules:
       - check-success=installer
       - check-success=installer_test (macos-latest)
       - check-success=installer_test (ubuntu-latest)
-      - check-success=tests (macos-latest)
+      - check-success=tests (macos-14)
       - check-success=tests (ubuntu-24.04)
-      - check-success=installer_test (macos-latest)
+      - check-success=installer_test (macos-14)
       - check-success=installer_test (ubuntu-24.04)
       - check-success=vm_tests
     merge_method: rebase
diff --git a/doc/manual/src/development/testing.md b/doc/manual/src/development/testing.md
index 4fac8abcc..ab6c66cc3 100644
--- a/doc/manual/src/development/testing.md
+++ b/doc/manual/src/development/testing.md
@@ -308,7 +308,7 @@ Creating a Cachix cache for your installer tests and adding its authorisation to
   - `armv7l-linux`
   - `x86_64-darwin`
 
-- The `installer_test` job (which runs on `ubuntu-24.04` and `macos-latest`) will try to install Nix with the cached installer and run a trivial Nix command.
+- The `installer_test` job (which runs on `ubuntu-24.04` and `macos-14`) will try to install Nix with the cached installer and run a trivial Nix command.
 
 ### One-time setup