The primary purpose of user acceptance testing (UAT) in software development is to validate that the software meets the business requirements and is ready for deployment. Conducted by end-users or stakeholders, UAT focuses on ensuring that the system functions as intended in real-world scenarios. This stage provides an opportunity for users to identify any issues or areas for improvement before the software goes live. By engaging users in this process, UAT plays a critical role in enhancing product quality and overall user satisfaction.