ASP.NET MVC (Model-View-Controller) is a software architectural pattern for creating web applications. It separates an application into three main components: the model, the view, and the controller.

1. Model: The model is responsible for managing the data and the business logic of the application. It represents the application’s data and defines how it is structured and manipulated. It also interacts with the database and performs data validation and business rules.

2. View: The view is responsible for presenting the user interface of the application. It displays the data to the user and handles user input. It can be a web page, a form, or any other user interface element.

3. Controller: The controller is responsible for handling user input and coordinating the flow of data between the model and the view. It receives requests from the user, interacts with the model to retrieve or manipulate data, and then selects the appropriate view to display the result.

The ASP.NET MVC architecture promotes separation of concerns and allows for easier development and maintenance of web applications. It provides a clear separation between the user interface, the data and business logic, and the control flow. This makes it easier to test and modify each component individually without affecting the others. Additionally, it supports code reuse, as the model and business logic can be reused across multiple views and controllers.