diff --git a/devel/Makefile b/devel/Makefile
index ae0dd2cdf729..73b60dc13ce9 100644
--- a/devel/Makefile
+++ b/devel/Makefile
@@ -1503,6 +1503,7 @@
     SUBDIR += mercurialeclipse
     SUBDIR += mergify
     SUBDIR += meson
+    SUBDIR += microsoft-gsl
     SUBDIR += mill
     SUBDIR += mimalloc
     SUBDIR += mime
diff --git a/devel/microsoft-gsl/Makefile b/devel/microsoft-gsl/Makefile
new file mode 100644
index 000000000000..108cab46f920
--- /dev/null
+++ b/devel/microsoft-gsl/Makefile
@@ -0,0 +1,21 @@
+# $FreeBSD$
+
+PORTNAME=	microsoft-gsl
+DISTVERSIONPREFIX=	v
+DISTVERSION=	2.1.0
+CATEGORIES=	devel
+
+MAINTAINER=	henry.hu.sh@gmail.com
+COMMENT=	Guidelines Support Library
+
+LICENSE=	MIT
+LICENSE_FILE=	${WRKSRC}/LICENSE
+
+USES=		cmake
+USE_GITHUB=	yes
+GH_ACCOUNT=	microsoft
+GH_PROJECT=	GSL
+CMAKE_OFF=	GSL_TEST
+NO_ARCH=	yes
+
+.include <bsd.port.mk>
diff --git a/devel/microsoft-gsl/distinfo b/devel/microsoft-gsl/distinfo
new file mode 100644
index 000000000000..24811baac456
--- /dev/null
+++ b/devel/microsoft-gsl/distinfo
@@ -0,0 +1,3 @@
+TIMESTAMP = 1583121165
+SHA256 (microsoft-GSL-v2.1.0_GH0.tar.gz) = ef73814657b073e1be86c8f7353718771bf4149b482b6cb54f99e79b23ff899d
+SIZE (microsoft-GSL-v2.1.0_GH0.tar.gz) = 67289
diff --git a/devel/microsoft-gsl/pkg-descr b/devel/microsoft-gsl/pkg-descr
new file mode 100644
index 000000000000..2f776aed3593
--- /dev/null
+++ b/devel/microsoft-gsl/pkg-descr
@@ -0,0 +1,11 @@
+The Guidelines Support Library (GSL) contains functions and types that are
+suggested for use by the C++ Core Guidelines maintained by the Standard C++
+Foundation. This repo contains Microsoft's implementation of GSL.
+
+The library includes types like span<T>, string_span, owner<> and others.
+
+The entire implementation is provided inline in the headers under the gsl
+directory. The implementation generally assumes a platform that implements
+C++14 support. There are specific workarounds to support MSVC 2015.
+
+WWW: https://github.com/microsoft/GSL
diff --git a/devel/microsoft-gsl/pkg-plist b/devel/microsoft-gsl/pkg-plist
new file mode 100644
index 000000000000..ac814ac6490a
--- /dev/null
+++ b/devel/microsoft-gsl/pkg-plist
@@ -0,0 +1,9 @@
+include/gsl/gsl
+include/gsl/gsl_algorithm
+include/gsl/gsl_assert
+include/gsl/gsl_byte
+include/gsl/gsl_util
+include/gsl/multi_span
+include/gsl/pointers
+include/gsl/span
+include/gsl/string_span