DescriptionWe describe shmem4py, a Python wrapper for the OpenSHMEM application programming interface (API) which follows a design similar to that of the well-known mpi4py package. OpenSHMEM is a descendant of the one-sided communication library for the Cray T3D and it is known for its uncompromising performance for low-latency and high-throughput use cases involving one-sided and collective communication. OpenSHMEM is arguably one of the most efficient and portable abstractions for modern network architectures. Thanks to tight interoperability with NumPy, shmem4py provides a convenient parallel programming framework leveraging both the high-productivity NumPy feature set and the high-performance networking capabilities of OpenSHMEM. This paper discusses the design and performance characteristics of shmem4py in a variety of communication patterns relative to lower-level languages (C) as well as MPI and mpi4py.