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. Developers can apply aspects to various parts of the program without modifying the core code, using techniques like weaving. This approach enhances code reusability and reduces redundancy, leading to more efficient software development.