diff --git a/.github/workflows/test_cpp.yml b/.github/workflows/test_cpp.yml
index 6c095a2171..35ecae8633 100644
--- a/.github/workflows/test_cpp.yml
+++ b/.github/workflows/test_cpp.yml
@@ -426,6 +426,12 @@ jobs:
           arch: ${{ matrix.windows-arch || 'x64' }}
           vsversion: ${{ matrix.vsversion }}
 
+      # Workaround for Abseil incompatibility with CMake 3.30 (b/352354235).
+      - name: Downgrade CMake
+        if: ${{ runner.os == 'Windows' }}
+        run: choco install cmake --version 3.29.6 --force
+        shell: bash
+
       # Workaround for incompatibility between gcloud and windows-2019 runners.
       - name: Install Python
         if: ${{ matrix.python-version }}