diff --git a/var/spack/repos/builtin/packages/gsi-ncdiag/package.py b/var/spack/repos/builtin/packages/gsi-ncdiag/package.py
new file mode 100644
index 0000000000..a01a32c39c
--- /dev/null
+++ b/var/spack/repos/builtin/packages/gsi-ncdiag/package.py
@@ -0,0 +1,30 @@
+# Copyright 2013-2023 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack.package import *
+
+
+class GsiNcdiag(CMakePackage):
+    """GSI NetCDF Diagnostics Library and Utility Tools"""
+
+    homepage = "https://github.com/NOAA-EMC/GSI-ncdiag"
+    url = "https://github.com/NOAA-EMC/GSI-ncdiag/archive/refs/tags/v1.0.0.tar.gz"
+
+    maintainers = ["ulmononian"]
+
+    version("1.0.0", sha256="7251d6139c2bc1580db5f7f019e10a4c73d188ddd52ccf21ecc9e39d50a6af51")
+
+    variant("serial", default=True, description="Enable Serial NetCDF diagnostics")
+
+    depends_on("mpi")
+    depends_on("netcdf-fortran@4.5.2:")
+
+    def cmake_args(self):
+        args = [self.define_from_variant("ENABLE_NCDIAG_SERIAL", "serial")]
+
+        args.append(self.define("CMAKE_C_COMPILER", self.spec["mpi"].mpicc))
+        args.append(self.define("CMAKE_Fortran_COMPILER", self.spec["mpi"].mpifc))
+
+        return args