diff --git a/build_scripts/qt/compilers/clang-msvc.pri b/build_scripts/qt/compilers/clang-msvc.pri
index 187db03..5f070cb 100644
--- a/build_scripts/qt/compilers/clang-msvc.pri
+++ b/build_scripts/qt/compilers/clang-msvc.pri
@@ -8,6 +8,8 @@ include(common-msvc.pri)
 #clang-msvc does not enable the c++17 flag with qmake's c++1z flag.
 QMAKE_CXXFLAGS += /std:c++17
 
+QMAKE_CXXFLAGS += -Wextra
+
 QMAKE_CXXFLAGS += -Wshadow
 
 QMAKE_CXXFLAGS += -Wold-style-cast
diff --git a/build_scripts/qt/compilers/clang.pri b/build_scripts/qt/compilers/clang.pri
index cb16a71..67764aa 100644
--- a/build_scripts/qt/compilers/clang.pri
+++ b/build_scripts/qt/compilers/clang.pri
@@ -1,3 +1,5 @@
+QMAKE_CXXFLAGS += -Wextra
+
 QMAKE_CXXFLAGS += -Werror
 #All includes from the third-party directory will not warn.
 QMAKE_CXXFLAGS += --system-header-prefix=third-party
diff --git a/build_scripts/qt/compilers/gcc.pri b/build_scripts/qt/compilers/gcc.pri
index 4f26c33..6f1e1ea 100644
--- a/build_scripts/qt/compilers/gcc.pri
+++ b/build_scripts/qt/compilers/gcc.pri
@@ -1,6 +1,8 @@
 #g++-7 is needed for C++17 features. travis does not supply this by default.
 QMAKE_CXX = g++-7
 
+QMAKE_CXXFLAGS += -Wextra
+
 QMAKE_CXXFLAGS += -Werror
 
 QMAKE_CXXFLAGS += -Wshadow