Aspect-Oriented Programming (AOP) is a programming paradigm that aims to increase modularity by allowing the separation of cross-cutting concerns. These concerns, such as logging, security, and error handling, often affect multiple parts of a program. AOP enables developers to define these concerns separately from the main business logic, making the code cleaner and easier to maintain. In AOP, aspects are the modules that encapsulate these cross-cutting concerns. They can be applied to various points in a program, known as join points, using a mechanism called advice. This approach helps improve code reusability and reduces redundancy, ultimately leading to more efficient software development.