PyTOPS: A Python based tool for TOPSIS. The Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method determines the best solution from a set of alternatives with certain attributes. The best alternative is chosen based on its Euclidean distance from the ideal solution. TOPSIS is widely used in various multi-attribute decision making problems such as supply chain logistics, marketing management, environmental management or chemical engineering. Despite the extensive use of this method, there is no free and open-source software (FOSS) for TOPSIS with comprehensive post-analysis extensions. Therefore, this paper describes a Python-3 based tool PyTOPS for TOPSIS with the Berkeley Software Distribution (BSD)-3-Clause license.