PyQt5 is a Python package that allows you to develop graphical user interfaces in Python. It is available on Windows, MacOS, and Linux and the GUIs that you create will have the look and feel of your native operating system. It is available under an open source license so you can get started with no cost to you. If you love the power of Python and all of the thousands of packages available for scientific and database applications, but wish you could provide your users with something other than a command line interface, PyQt5 is for you.