diff --git a/astro/phd2/Makefile b/astro/phd2/Makefile
index a4eea19ffa7e..fafef741dc30 100644
--- a/astro/phd2/Makefile
+++ b/astro/phd2/Makefile
@@ -21,6 +21,7 @@ USES=		cmake eigen:3 gettext ninja pkgconfig xorg
 USE_GITHUB=	yes
 GH_ACCOUNT=	OpenPHDGuiding
 
+USE_CXXSTD=	c++14 # googletest 1.13
 USE_WX=		3.2+
 USE_XORG=	x11