PyRth is a robust, open‐source Python package for advanced thermal transient analysis using advanced Network Identification by Deconvolution (NID) algorithms. Designed to process data from thermal measurement devices like the T3Ster, PyRth uses state‐of‐the‐art algorithms to extract critical thermal parameters—such as thermal resistance, capacitance, and the thermal structure function—from raw thermal transient data. By converting measurement data into detailed thermal RC network models, PyRth supports precise device thermal characterization, quality control, and thermal management optimization. Fully documented and easily integrated into Python workflows, PyRth is available on PyPI and GitHub, making it an ideal solution for engineers and researchers in electronics thermal testing and reliability analysis.