React Suspense is a feature of the React library that allows components to fall back to another component while loading, providing a cohesive user interface and improving user experience by preventing UI bugs such as missing images and media. It's a built-in React component that wraps around another component to change its behavior, suspending rendering until an operation completes. Suspense can be used with data fetching and lazy loading of components, allowing for render-as-you-fetch, which provides better performance and UX by rendering some data earlier than others. The fallback property allows setting a different component as a placeholder while the desired component is still loading, improving perceived performance and reducing code splitting. React Suspense simplifies code and improves performance, making it easier to handle async operations without writing custom code.