diff --git a/src/network/socket/qnativesocketengine_win.cpp b/src/network/socket/qnativesocketengine_win.cpp
index d578e5230fd..16d974a68be 100644
--- a/src/network/socket/qnativesocketengine_win.cpp
+++ b/src/network/socket/qnativesocketengine_win.cpp
@@ -2,9 +2,6 @@
 // Copyright (C) 2016 Intel Corporation.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
-// Prevent windows system header files from defining min/max as macros.
-#define NOMINMAX 1
-
 #include <winsock2.h>
 #include <ws2tcpip.h>
 
diff --git a/src/plugins/sqldrivers/oci/qsql_oci.cpp b/src/plugins/sqldrivers/oci/qsql_oci.cpp
index b670efc15be..1a9eb041b30 100644
--- a/src/plugins/sqldrivers/oci/qsql_oci.cpp
+++ b/src/plugins/sqldrivers/oci/qsql_oci.cpp
@@ -30,14 +30,7 @@
 #define _int64 __int64
 #endif
 
-
 #include <oci.h>
-#ifdef max
-#undef max
-#endif
-#ifdef min
-#undef min
-#endif
 
 #include <stdlib.h>
 
diff --git a/src/plugins/tls/openssl/qdtls_openssl.cpp b/src/plugins/tls/openssl/qdtls_openssl.cpp
index 78288d8dd1b..fc07a29ec86 100644
--- a/src/plugins/tls/openssl/qdtls_openssl.cpp
+++ b/src/plugins/tls/openssl/qdtls_openssl.cpp
@@ -1,10 +1,6 @@
 // Copyright (C) 2018 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
-#ifndef NOMINMAX
-#define NOMINMAX
-#endif // NOMINMAX
-
 #include <QtNetwork/private/qnativesocketengine_p_p.h>
 
 #include "qsslsocket_openssl_symbols_p.h"
diff --git a/src/testlib/qjunittestlogger.cpp b/src/testlib/qjunittestlogger.cpp
index 8e2b917055c..4ee5788beea 100644
--- a/src/testlib/qjunittestlogger.cpp
+++ b/src/testlib/qjunittestlogger.cpp
@@ -9,13 +9,6 @@
 #include <QtTest/private/qbenchmark_p.h>
 #include <QtTest/private/qtestlog_p.h>
 
-#ifdef min // windows.h without NOMINMAX is included by the benchmark headers.
-#  undef min
-#endif
-#ifdef max
-#  undef max
-#endif
-
 #include <QtCore/qlibraryinfo.h>
 
 #include <string.h>
diff --git a/src/testlib/qplaintestlogger.cpp b/src/testlib/qplaintestlogger.cpp
index 9f61004c2ce..4bafacb10fa 100644
--- a/src/testlib/qplaintestlogger.cpp
+++ b/src/testlib/qplaintestlogger.cpp
@@ -16,13 +16,6 @@
 #include <stdlib.h>
 #include <string.h>
 
-#ifdef min // windows.h without NOMINMAX is included by the benchmark headers.
-#  undef min
-#endif
-#ifdef max
-#  undef max
-#endif
-
 #include <QtCore/QByteArray>
 #include <QtCore/qmath.h>
 #include <QtCore/QLibraryInfo>
diff --git a/tests/auto/network/kernel/qhostinfo/tst_qhostinfo.cpp b/tests/auto/network/kernel/qhostinfo/tst_qhostinfo.cpp
index 273bf3a0357..e6704c36236 100644
--- a/tests/auto/network/kernel/qhostinfo/tst_qhostinfo.cpp
+++ b/tests/auto/network/kernel/qhostinfo/tst_qhostinfo.cpp
@@ -7,9 +7,6 @@
 // (except qglobal.h), or else you'll get tons of compile errors
 #include <qglobal.h>
 
-// To prevent windows system header files from re-defining min/max
-#define NOMINMAX 1
-
 #if defined(Q_OS_WIN)
 # include <winsock2.h>
 # include <ws2tcpip.h>
diff --git a/tests/auto/network/socket/qtcpserver/tst_qtcpserver.cpp b/tests/auto/network/socket/qtcpserver/tst_qtcpserver.cpp
index 90e6f3da8e4..f42d0497fef 100644
--- a/tests/auto/network/socket/qtcpserver/tst_qtcpserver.cpp
+++ b/tests/auto/network/socket/qtcpserver/tst_qtcpserver.cpp
@@ -2,8 +2,6 @@
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
 
 #include <qglobal.h>
-// To prevent windows system header files from re-defining min/max
-#define NOMINMAX 1
 #if defined(_WIN32)
 #include <winsock2.h>
 #else
diff --git a/tests/auto/network/socket/qtcpsocket/tst_qtcpsocket.cpp b/tests/auto/network/socket/qtcpsocket/tst_qtcpsocket.cpp
index 5dc12b924fb..c16717e95a7 100644
--- a/tests/auto/network/socket/qtcpsocket/tst_qtcpsocket.cpp
+++ b/tests/auto/network/socket/qtcpsocket/tst_qtcpsocket.cpp
@@ -4,8 +4,6 @@
 
 #include <qglobal.h>
 
-// To prevent windows system header files from re-defining min/max
-#define NOMINMAX 1
 #if defined(_WIN32)
 #include <winsock2.h>
 #else