diff --git a/include/mio/mmap.hpp b/include/mio/mmap.hpp
index def559a..596ad6b 100644
--- a/include/mio/mmap.hpp
+++ b/include/mio/mmap.hpp
@@ -490,3 +490,5 @@ mmap_sink make_mmap_sink(const MappingToken& token, std::error_code& error)
 #include "detail/mmap.ipp"
 
 #endif // MIO_MMAP_HEADER
+
+#undef max
diff --git a/single_include/mio/mio.hpp b/single_include/mio/mio.hpp
index 6ad6a74..79455b8 100644
--- a/single_include/mio/mio.hpp
+++ b/single_include/mio/mio.hpp
@@ -1761,3 +1761,5 @@ using shared_ummap_sink = basic_shared_mmap_sink<unsigned char>;
 } // namespace mio
 
 #endif // MIO_SHARED_MMAP_HEADER
+
+#undef max