ASP.NET and ASP.NET MVC are both web application frameworks developed by Microsoft, but they have some key differences.

ASP.NET is a framework for building web applications, websites, and services using a traditional model-view-controller (MVC) architecture. It provides a lot of features and functionalities out-of-the-box, including a rich set of controls and libraries for common tasks. The main advantage of ASP.NET is that it's easy to get started with and provides a lot of built-in functionality, which makes it a good choice for many simple web application projects.

ASP.NET MVC, on the other hand, is a variation of ASP.NET that follows a more traditional MVC pattern. It's designed to provide more control over the application's behavior and structure, and to allow for a more test-driven development approach. The MVC pattern provides a clear separation of concerns between the data (model), presentation (view), and behavior (controller) of an application. This makes it easier to maintain and scale the application as it grows.

In summary, ASP.NET is a good choice for simple, straightforward web applications that require a lot of built-in functionality. ASP.NET MVC is a better choice for more complex applications that need more control over the application's behavior and structure, and that benefit from a more test-driven development approach.