diff --git a/var/spack/repos/builtin/packages/parallelio/package.py b/var/spack/repos/builtin/packages/parallelio/package.py
new file mode 100644
index 0000000000..ec3334cfc6
--- /dev/null
+++ b/var/spack/repos/builtin/packages/parallelio/package.py
@@ -0,0 +1,42 @@
+# Copyright 2013-2021 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 import *
+
+
+class Parallelio(CMakePackage):
+    """The Parallel IO libraries (PIO) are high-level parallel I/O C and
+    Fortran libraries for applications that need to do netCDF I/O from
+    large numbers of processors on a HPC system."""
+
+    homepage = "https://ncar.github.io/ParallelIO/"
+    url      = "https://github.com/NCAR/ParallelIO/archive/pio2_5_2.tar.gz"
+
+    maintainers = ['tkameyama']
+
+    version('2_5_2', sha256='935bc120ef3bf4fe09fb8bfdf788d05fb201a125d7346bf6b09e27ac3b5f345c')
+
+    variant('pnetcdf', default=False, description='enable pnetcdf')
+
+    depends_on('mpi')
+    depends_on('netcdf-c +mpi', type='link')
+    depends_on('netcdf-fortran', type='link')
+    depends_on('parallel-netcdf', type='link', when='+pnetcdf')
+
+    def cmake_args(self):
+        define = self.define
+        spec = self.spec
+        env['CC'] = spec['mpi'].mpicc
+        env['FC'] = spec['mpi'].mpifc
+        args = [
+            define('NetCDF_C_PATH', spec['netcdf-c'].prefix),
+            define('NetCDF_Fortran_PATH', spec['netcdf-fortran'].prefix),
+        ]
+        if spec.satisfies('+pnetcdf'):
+            args.extend([
+                define('PnetCDF_C_PATH', spec['parallel-netcdf'].prefix),
+                define('PnetCDF_Fortran_PATH', spec['parallel-netcdf'].prefix),
+            ])
+        return args