面向对象编程（英语：Object-oriented programming，缩写：OOP）是种具有对象概念的程序编程典范，同时也是一种进程开发的方法。它可能包含数据、属性、代码与方法。对象则指的是类的实例。它将对象作为进程的基本单元，将进程和数据封装其中，以提高软件的重用性、灵活性和扩展性，对象里的进程可以访问及经常修改对象相关连的数据。在面向对象程序编程里，电脑程序会被设计成彼此相关的对象。

面向对象进程设计可以看作一种在进程中包含各种独立而又互相调用的对象的思想，这与传统的思想刚好相反：传统的进程设计主张将进程看作一系列函数的集合，或者直接就是一系列对电脑下达的指令。面向对象进程设计中的每一个对象都应该能够接受数据、处理数据并将数据传达给其它对象，因此它们都可以被看作一个小型的“机器”，即对象。目前已经被证实的是，面向对象进程设计推广了进程的灵活性和可维护性，并且在大型项目设计中广为应用。此外，支持者声称面向对象进程设计要比以往的做法更加便于学习，因为它能够让人们更简单地设计并维护进程，使得进程更加便于分析、设计、理解。反对者在某些领域对此予以否认。

Object-oriented programming (OOP) is a programming paradigm based on the concept of "objects", which may contain data, in the form of fields, often known as attributes; and code, in the form of procedures, often known as methods. A feature of objects is that an object's procedures can access and often modify the data fields of the object with which they are associated (objects have a notion of "this" or "self"). In OOP, computer programs are designed by making them out of objects that interact with one another. There is significant diversity of OOP languages, but the most popular ones are class-based, meaning that objects are instances of classes, which typically also determine their type.