diff --git a/Toolchain/BuildClang.sh b/Toolchain/BuildClang.sh
index 27f6d3f392..465a52a2db 100755
--- a/Toolchain/BuildClang.sh
+++ b/Toolchain/BuildClang.sh
@@ -115,6 +115,43 @@ then
     exit 1
 fi
 
+# === CHECK CACHE AND REUSE ===
+
+pushd "$DIR"
+    if [ "$TRY_USE_LOCAL_TOOLCHAIN" = "y" ]; then
+        mkdir -p Cache
+        echo "Cache (before):"
+        ls -l Cache
+        CACHED_TOOLCHAIN_ARCHIVE="Cache/ToolchainBinariesGithubActions.tar.gz"
+        if [ -r "${CACHED_TOOLCHAIN_ARCHIVE}" ] ; then
+            echo "Cache at ${CACHED_TOOLCHAIN_ARCHIVE} exists!"
+            echo "Extracting toolchain from cache:"
+            if tar xzf "${CACHED_TOOLCHAIN_ARCHIVE}" ; then
+                 echo "Done 'building' the toolchain."
+                 echo "Cache unchanged."
+                 exit 0
+            else
+                echo
+                echo
+                echo
+                echo "Could not extract cached toolchain archive."
+                echo "This means the cache is broken and *should be removed*!"
+                echo "As Github Actions cannot update a cache, this will unnecessarily"
+                echo "slow down all future builds for this hash, until someone"
+                echo "resets the cache."
+                echo
+                echo
+                echo
+                rm -f "${CACHED_TOOLCHAIN_ARCHIVE}"
+            fi
+        else
+            echo "Cache at ${CACHED_TOOLCHAIN_ARCHIVE} does not exist."
+            echo "Will rebuild toolchain from scratch, and save the result."
+        fi
+    fi
+    echo "::group::Actually building Toolchain"
+popd
+
 # === DOWNLOAD AND PATCH ===
 
 pushd "$DIR/Tarballs"
@@ -351,3 +388,19 @@ pushd "$DIR/Build/clang/$ARCH"
         buildstep "binutils/install" "$MAKE" install || exit 1
     popd
 popd
+
+# === SAVE TO CACHE ===
+pushd "$DIR"
+    if [ "$TRY_USE_LOCAL_TOOLCHAIN" = "y" ]; then
+        echo "::endgroup::"
+        echo "Building cache tar:"
+
+        echo "Building cache tar:"
+
+        rm -f "${CACHED_TOOLCHAIN_ARCHIVE}"  # Just in case
+
+        tar czf "${CACHED_TOOLCHAIN_ARCHIVE}" Local/
+        echo "Cache (after):"
+        ls -l Cache
+    fi
+popd