User Acceptance Testing (UAT) is the final phase of software testing where actual end users verify that a system works correctly for their needs before it goes live. Unlike technical testing by developers, UAT confirms the system meets business requirements from users' perspectives. UAT involves testing realistic scenarios, workflows, and use cases that reflect how the system will actually be used. Issues discovered during UAT must be resolved before deployment. Government IT projects include UAT phases where staff who will use new systems verify functionality. Effective UAT requires representative users, realistic test scenarios, and time to address identified issues. Skipping or rushing UAT risks deploying systems that don't meet user needs despite passing technical tests.