diff --git a/config.pri b/config.pri
index b89d5404..3c6d5620 100644
--- a/config.pri
+++ b/config.pri
@@ -4,6 +4,9 @@
 
 CONFIG += c++11
 
+unix:QMAKE_CXXFLAGS_RELEASE += -DNDEBUG
+win32:QMAKE_CXXFLAGS_RELEASE += /DNDEBUG
+
 # check Qt version
 QT_VERSION = $$[QT_VERSION]
 QT_VERSION = $$split(QT_VERSION, ".")