diff --git a/.github/workflows/desktop-build.yml b/.github/workflows/desktop-build.yml
index 4a0b309ca..728dbf3f0 100644
--- a/.github/workflows/desktop-build.yml
+++ b/.github/workflows/desktop-build.yml
@@ -278,7 +278,7 @@ jobs:
     continue-on-error: ${{matrix.allow-failure == 'yes'}}
     env:
       # Common parameters for all macOS builds
-      QT_VERSION: 6.6.*
+      QT_VERSION: 6.6.3
       QT_ARCH: clang_64
       QT_MODULES: "qtimageformats qtmultimedia qtwebsockets"
       # Build-specific environment variables
@@ -303,17 +303,29 @@ jobs:
           ccache-key-prefix: ccache-${{matrix.os}}-${{matrix.soc}}-${{matrix.type}}
           gh-token: ${{ secrets.GITHUB_TOKEN }}
 
+      - name: Add RUNNER_WORKSPACE to GitHub environment variables
+        run: echo "RUNNER_WORKSPACE=$RUNNER_WORKSPACE" >> $GITHUB_ENV
+
+      - name: Restore thin Qt libraries
+        id: restore_qt
+        uses: actions/cache/restore@v4
+        with:
+          path: ${{ env.RUNNER_WORKSPACE }}/Qt
+          key: qt-macos-${{ matrix.soc }}-${{ env.QT_VERSION }}
+
       # Using jurplel/install-qt-action to install Qt without using brew
       # qt build using vcpkg either just fails or takes too long to build
       - name: Install Qt ${{env.QT_VERSION}}
+        if: steps.restore_qt.outputs.cache-hit != 'true'
         uses: jurplel/install-qt-action@v4
         with:
-          cache: true # qt caches take too much space for macOS (1.1Gi)
+          cache: false # caching manually after thinning
           version: ${{env.QT_VERSION}}
           arch: ${{env.QT_ARCH}}
           modules: ${{env.QT_MODULES}}
 
       - name: Thin Qt libraries
+        if: steps.restore_qt.outputs.cache-hit != 'true'
         run: |
           export ARCH=$(uname -m)
           export NPROC=$(sysctl -n hw.ncpu)
@@ -322,6 +334,13 @@ jobs:
             xargs -0 -n1 -P "$NPROC" sh -c \
               'file -b --mime-type "$0" | grep -q "application/x-mach-binary" && lipo "$0" -thin "$ARCH" -output "$0" || true'
 
+      - name: Cache thin Qt libraries
+        if: steps.restore_qt.outputs.cache-hit != 'true'
+        uses: actions/cache/save@v4
+        with:
+          path: ${{ env.RUNNER_WORKSPACE }}/Qt
+          key: qt-macos-${{ matrix.soc }}-${{ env.QT_VERSION }}
+
       - name: Setup vcpkg cache
         id: vcpkg-cache
         uses: TAServers/vcpkg-cache@v3
@@ -343,6 +362,7 @@ jobs:
           VCPKG_DISABLE_METRICS: 1
           VCPKG_BINARY_SOURCES: 'clear;files,${{ steps.vcpkg-cache.outputs.path }},readwrite'
           TARGET_MACOS_VERSION: ${{ matrix.override_target }}
+          QTDIR: ${{ env.RUNNER_WORKSPACE }}/Qt/${{ env.QT_VERSION }}/macos
         run: .ci/compile.sh --server --test --ccache "$CCACHE_SIZE" --vcpkg
 
       - name: Sign app bundle