Controllers in AngularJS are JavaScript functions that are used to build the logic for AngularJS applications. They play a crucial role in managing the data and behavior of the application. Controllers act as the bridge between the view (HTML) and the model (data), handling the interaction and facilitating two-way data binding.

Key Features of Controllers

1. Scope Binding: Controllers are used to bind data to the view via the $scope object. The $scope object is a special JavaScript object that plays the role of joining the controller with the view.
2. Methods: Controllers can define methods to handle events and business logic.
3. Modularity: Controllers help in organizing the code into manageable, testable, and reusable components.