Request caching allows you to cache the response of a specific request and serve subsequent requests with the cached response, eliminating the need to process the request again. In ASP.NET Core, you can use the ResponseCaching middleware to enable request caching. By adding the middleware to the pipeline and configuring cache-related options, you can cache responses based on criteria such as the request URL, query parameters, or headers. Request caching can significantly improve the performance of frequently accessed endpoints.