A ViewModel is a component in software architecture, particularly in the Model-View-ViewModel (MVVM) pattern. It acts as a bridge between the user interface (UI) and the underlying data model. The ViewModel holds the data and business logic, allowing the UI to display information without directly interacting with the data source. By using a ViewModel, developers can separate concerns, making the code more manageable and testable. The ViewModel responds to user actions and updates the UI accordingly, ensuring that the user experience is smooth and responsive. This separation enhances maintainability and scalability in applications.