diff --git a/lib/clang/llvm.build.mk b/lib/clang/llvm.build.mk
--- a/lib/clang/llvm.build.mk
+++ b/lib/clang/llvm.build.mk
@@ -119,7 +119,6 @@
 .endif
 .endif
 
-CXXSTD?=	c++17
 CXXFLAGS+=	-fno-exceptions
 CXXFLAGS+=	-fno-rtti
 .if ${.MAKE.OS} == "FreeBSD" || !defined(BOOTSTRAPPING)
diff --git a/lib/libc/tests/stdlib/Makefile b/lib/libc/tests/stdlib/Makefile
--- a/lib/libc/tests/stdlib/Makefile
+++ b/lib/libc/tests/stdlib/Makefile
@@ -58,8 +58,6 @@
 
 CFLAGS+=	-I${.CURDIR}
 
-CXXSTD.cxa_thread_atexit_test=	c++11
-CXXSTD.cxa_thread_atexit_nothr_test=	c++11
 LIBADD.cxa_thread_atexit_test+=		pthread
 
 # Tests that requires Blocks feature
diff --git a/lib/libclang_rt/Makefile.inc b/lib/libclang_rt/Makefile.inc
--- a/lib/libclang_rt/Makefile.inc
+++ b/lib/libclang_rt/Makefile.inc
@@ -33,4 +33,3 @@
 CXXFLAGS+=	-fvisibility=hidden
 CFLAGS+=	-I${CRTSRC}/include
 CFLAGS+=	-I${CRTSRC}/lib
-CXXSTD=		c++17
diff --git a/lib/libcxxrt/Makefile b/lib/libcxxrt/Makefile
--- a/lib/libcxxrt/Makefile
+++ b/lib/libcxxrt/Makefile
@@ -23,7 +23,6 @@
 
 WARNS?=		0
 CFLAGS+=	-isystem ${SRCDIR} -nostdinc++
-CXXSTD?=	c++14
 
 .if exists(Version.map.${MACHINE})
 VERSION_MAP=	${.CURDIR}/Version.map.${MACHINE}
diff --git a/lib/libgcc_eh/Makefile.inc b/lib/libgcc_eh/Makefile.inc
--- a/lib/libgcc_eh/Makefile.inc
+++ b/lib/libgcc_eh/Makefile.inc
@@ -38,7 +38,6 @@
 CFLAGS+=	-D_LIBUNWIND_IS_NATIVE_ONLY
 CFLAGS+=	-D_LIBUNWIND_USE_FRAME_HEADER_CACHE
 CXXFLAGS+=	-fno-rtti
-CXXSTD?=	c++11
 STATIC_CXXFLAGS+= -fvisibility=hidden -fPIC
 # Probably need to just move this earlier or use CXXFLAGS
 .if ${MK_DIRDEPS_BUILD} == "yes"
diff --git a/lib/libomp/Makefile b/lib/libomp/Makefile
--- a/lib/libomp/Makefile
+++ b/lib/libomp/Makefile
@@ -57,7 +57,6 @@
 CXXFLAGS+=	-fvisibility-inlines-hidden
 CXXFLAGS+=	-fno-exceptions
 CXXFLAGS+=	-fno-rtti
-CXXSTD=		c++17
 
 .if ${COMPILER_TYPE} == "clang"
 .if ${MACHINE_CPUARCH} == "i386"
diff --git a/lib/ofed/libibnetdisc/Makefile b/lib/ofed/libibnetdisc/Makefile
--- a/lib/ofed/libibnetdisc/Makefile
+++ b/lib/ofed/libibnetdisc/Makefile
@@ -29,7 +29,6 @@
 CFLAGS+=	-DHAVE_CONFIG_H=1
 CFLAGS+=	-I${_spath}
 CFLAGS+=	-I${SYSROOT:U${DESTDIR}}/${INCLUDEDIR}/infiniband
-CXXSTD=		c++11
 VERSION_MAP=	${_spath}/libibnetdisc.map
 
 .include <bsd.lib.mk>
diff --git a/libexec/atf/atf-pytest-wrapper/Makefile b/libexec/atf/atf-pytest-wrapper/Makefile
--- a/libexec/atf/atf-pytest-wrapper/Makefile
+++ b/libexec/atf/atf-pytest-wrapper/Makefile
@@ -4,7 +4,6 @@
 PACKAGE=	tests
 PROG_CXX=	atf_pytest_wrapper
 SRCS=		atf_pytest_wrapper.cpp
-CXXSTD=		c++17
 MAN=
 
 .include <bsd.prog.mk>
diff --git a/share/mk/bsd.sys.mk b/share/mk/bsd.sys.mk
--- a/share/mk/bsd.sys.mk
+++ b/share/mk/bsd.sys.mk
@@ -22,6 +22,8 @@
 CFLAGS+=	-std=${CSTD}
 .endif # CSTD
 
+CXXSTD?=	c++17
+
 .if !empty(CXXSTD)
 CXXFLAGS+=	-std=${CXXSTD}
 .endif
diff --git a/share/mk/googletest.test.inc.mk b/share/mk/googletest.test.inc.mk
--- a/share/mk/googletest.test.inc.mk
+++ b/share/mk/googletest.test.inc.mk
@@ -9,6 +9,4 @@
 # libgmock's, etc, headers.
 CXXFLAGS+=	-I${DESTDIR}${INCLUDEDIR}/private
 
-CXXSTD?=	c++14
-
 NO_WTHREAD_SAFETY=
diff --git a/tests/sys/fs/fusefs/Makefile b/tests/sys/fs/fusefs/Makefile
--- a/tests/sys/fs/fusefs/Makefile
+++ b/tests/sys/fs/fusefs/Makefile
@@ -89,7 +89,6 @@
 CXXFLAGS+=	-I${FUSEFS}
 CXXFLAGS+=	-I${MOUNT}
 .PATH:		${MOUNT}
-CXXSTD=		c++14
 
 LIBADD+=	pthread
 LIBADD+=	gmock gtest
diff --git a/usr.bin/dtc/Makefile b/usr.bin/dtc/Makefile
--- a/usr.bin/dtc/Makefile
+++ b/usr.bin/dtc/Makefile
@@ -6,8 +6,6 @@
 
 CXXFLAGS+=	-fno-rtti -fno-exceptions
 
-CXXSTD=	c++17
-
 NO_SHARED?=NO
 
 .include <bsd.prog.mk>
diff --git a/usr.sbin/pmc/Makefile b/usr.sbin/pmc/Makefile
--- a/usr.sbin/pmc/Makefile
+++ b/usr.sbin/pmc/Makefile
@@ -2,7 +2,6 @@
 
 PROG_CXX=	pmc
 MAN=	
-CXXSTD= c++14
 CWARNFLAGS.gcc+= -Wno-redundant-decls
 CFLAGS+= -I${SRCTOP}/lib/libpmcstat