The primary purpose of a debugger in programming is to identify and fix errors or bugs in code. Debuggers provide developers with tools to step through code execution, examine variable states, and analyze control flow, enabling them to pinpoint where issues arise. Effective use of a debugger can significantly enhance code quality by allowing developers to test different scenarios and ensure that the program behaves as expected. Debugging is essential in the software development lifecycle, ensuring that applications are reliable and perform optimally, thereby improving the overall user experience.