diff --git a/.github/workflows/cmake-multi-platform.yml b/.github/workflows/cmake-multi-platform.yml
index 0d7a495..2801a42 100644
--- a/.github/workflows/cmake-multi-platform.yml
+++ b/.github/workflows/cmake-multi-platform.yml
@@ -72,6 +72,8 @@ jobs:
         -S ${{ github.workspace }}
         -DCMAKE_INSTALL_PREFIX=${{github.workspace}}/local
         -DBUILD_PYTHON_MODULE=ON
+      env:
+          BOOST_ROOT: ${{ steps.install-boost.outputs.BOOST_ROOT }}
 
     - name: Build
       run: cmake --build ${{ steps.strings.outputs.build-output-dir }} --config Release