Aspect-oriented programming (AOP) is a programming paradigm that allows developers to separate cross-cutting concerns, such as logging, security, and transaction management, from the main business logic of a program. In AOP, aspects are defined as separate modules that encapsulate these cross-cutting concerns and can be applied to different parts of the codebase without affecting the core functionality. This approach helps to improve code modularity, reduce code duplication, and enhance code maintainability. AOP is often used in conjunction with object-oriented programming to address specific design issues and make complex systems easier to manage and understand.