pylinac is a Python library for performing TG-142 QA tasks on linear accelerators. It provides high-level analysis modules for common radiotherapy QA tests—VMAT, Winston-Lutz, PIPS, field analysis, planar imaging, log analysis, CT, and star shot—plus lower-level core modules for image handling, gamma analysis, ROI calculations, and structured results. The library is used as a dependency in clinical QA workflows and exposes a consistent API: instantiate an analysis class with a DICOM/log file path, call `.analyze(...)`, then access `.results_data()`, `.publish_pdf()`, or `.plot_analyzed_image()`.