Thonny is an integrated development environment for Python designed specifically for beginning programmers. It presents a simple user interface that was designed to be easy to explore and learn. The built-in debugger features several ways to visualize the execution of code. Particularly useful for beginners is Thonny's "faithful representation of function calls" where each function's context is displayed in a separate window, visually illustrating how recursive functions work. It also includes a step-by-step evaluation mode where the debugger shows how subexpressions are computed one piece at a time. The editor includes familiar features like code completion and highlighting of syntax errors, but also special highlighting of variables to distinguish variables with the same name in different scopes (e.g., inside different functions). Installers are available for Windows, macOS, and Linux computers. Thonny is a free software with code available from Bitbucket under the MIT license.