RestTemplate is a synchronous client provided by the Spring Framework for making HTTP requests in Java applications. It simplifies the process of interacting with RESTful web services by offering methods to perform common operations like GET, POST, PUT, and DELETE. With RestTemplate, developers can easily convert Java objects to JSON or XML and vice versa, making it straightforward to send and receive data. It also supports various features such as error handling, request/response interceptors, and customizable message converters, enhancing the flexibility and usability of HTTP communication in applications.