Load testing helps assess the performance and scalability of your Web API by simulating high user loads and measuring response times and resource utilization. In ASP.NET Core Web API, you can implement load testing using tools like Apache JMeter, LoadRunner, or Artillery. These tools allow you to configure and simulate concurrent requests, define test scenarios, and generate varying loads on your API. By analyzing the load test results, you can identify performance bottlenecks, optimize resource usage, and ensure that your Web API can handle the expected load. Load testing is crucial to ensure that your API can perform well under real-world conditions and meet the performance requirements of your application.