diff --git a/core/libs/prx/libc/src/Filesystem.cpp b/core/libs/prx/libc/src/Filesystem.cpp
index 258f10c3f..d7f191170 100644
--- a/core/libs/prx/libc/src/Filesystem.cpp
+++ b/core/libs/prx/libc/src/Filesystem.cpp
@@ -2,7 +2,9 @@
 #include <cerrno>
 #include <vector>
 #ifdef _WIN32
+#ifndef NOMINMAX
 #define NOMINMAX
+#endif
 #include <windows.h>
 #else
 #include <unistd.h>
diff --git a/core/libs/prx/libkernel/DirectMemory/Export.cpp b/core/libs/prx/libkernel/DirectMemory/Export.cpp
index 096519100..1cf4a14f0 100644
--- a/core/libs/prx/libkernel/DirectMemory/Export.cpp
+++ b/core/libs/prx/libkernel/DirectMemory/Export.cpp
@@ -7,7 +7,9 @@
 #include "prx/libkernel/DirectMemory/DirectMemory.hpp"
 #ifdef _WIN32
 #define WIN32_LEAN_AND_MEAN
+#ifndef NOMINMAX
 #define NOMINMAX
+#endif
 #include <windows.h>
 #else
 #include <cerrno>
diff --git a/core/libs/prx/libkernel/Module/src/DynamicLoader.cpp b/core/libs/prx/libkernel/Module/src/DynamicLoader.cpp
index 24a842615..d2604c94d 100644
--- a/core/libs/prx/libkernel/Module/src/DynamicLoader.cpp
+++ b/core/libs/prx/libkernel/Module/src/DynamicLoader.cpp
@@ -9,7 +9,9 @@
 #include <string>
 #include <vector>
 #ifdef _WIN32
+#ifndef NOMINMAX
 #define NOMINMAX
+#endif
 #include <windows.h>
 #else
 #include <dlfcn.h>
diff --git a/core/libs/tests/GuestAccess.cpp b/core/libs/tests/GuestAccess.cpp
index 723b9c090..0cce786ad 100644
--- a/core/libs/tests/GuestAccess.cpp
+++ b/core/libs/tests/GuestAccess.cpp
@@ -3,7 +3,9 @@
 #include <cstdlib>
 #include <fstream>
 #ifdef _WIN32
+#ifndef NOMINMAX
 #define NOMINMAX
+#endif
 #include <windows.h>
 #include <aclapi.h>
 #endif