diff --git a/win/installers.py b/win/installers.py
index 50b90f804f..8c8e8e153a 100644
--- a/win/installers.py
+++ b/win/installers.py
@@ -265,8 +265,7 @@ def install_boost(
     build_deps_cache.add_entry("BOOST_INSTALL_DIR", str(dependency_install_dir))
 
     # NOTE Boost is fast to build with a limited set of libraries, so it's rebuilt by default.
-    # TODO: consider reuse_boost and release/debug installations.
-    if reuse_boost and is_already_installed(dependency_install_dir):
+    if reuse_boost and is_already_installed(dependency_install_dir, expected_build_cfg=build_cfg):
         return
 
     BOOST_ZIP = f"boost-{BOOST_VERSION}-b2-nodocs.7z"
@@ -335,6 +334,8 @@ def install_boost(
         cwd=dependency_dir,
     )
 
+    mark_installation(dependency_install_dir, build_cfg)
+
 
 def install_opencollada(
     vs_cfg_vars: VsCfgResult,