Rate limiting helps prevent abuse or excessive usage of your Web API by limiting the number of requests per time interval from a client or IP address. In ASP.NET Core, you can implement rate limiting using libraries like AspNetCoreRateLimit or custom middleware. These libraries allow you to define rate limits based on various factors such as client, IP address, or API endpoint. When the limit is reached, you can respond with a specific HTTP status code or take other actions, such as delaying or rejecting the request. Rate limiting protects your Web API from excessive traffic and ensures fair usage.