Structural reliability methods enable probabilistic analysis and design of structures. Furthermore, these methods are essential for the calibration of structural design codes. PySTRA (Python Structural Reliability Analysis) is a free and open-source Python package for structural reliability analysis. Its flexibility and extensibility make it applicable to an extensive suite of problems. Along with core reliability analysis functionality, PySTRA includes methods for summarizing output. PySTRA is also closely integrated with the widely-used Python scientific packages such as NumPy, SciPy, and Pandas. This paper discusses the architecture, functionality, and basic usage for PySTRA. PySTRA is highly useful for reliability engineering scientists and practitioners, particularly structural engineers.