Unit testing is essential for verifying the correctness and functionality of your Web API's individual components. In ASP.NET Core Web API, you can implement unit testing using testing frameworks like xUnit, NUnit, or MSTest. You can write tests to cover various scenarios by mocking dependencies and setting up appropriate test data. Tools like Moq or NSubstitute can be used to create mock objects for dependencies. By executing the tests and asserting the expected results, you can validate the behavior of your Web API's methods, controllers, and services. Unit testing helps identify bugs early and provides confidence in the code's reliability.