西方化，又称西化、西洋化、欧美化，是指社会在产业、技术、法律、政治、经济、生活方式、饮食、语言、字母、宗教、哲学及价值方面采纳西方文化的进程。在最近多个世纪，西方化在全球都有普遍且促进的影响力。西方化通常是一个双向的过程，受到影响的社会驱使西方的影响力使之变成更加西方化的社会，以希望获得西方的生活或它的某部分。

西方化又与文化互渗和文化适应相关。文化互渗是指一个社会或文化里两个不同族群的持续接触所产生的转变，接触以后双方文化模式的转变是明显的。西方化在流行的说法是指西方扩张和殖民主义对当地社会的作用。

Westernization (USA) or Westernisation (UK) (see spelling differences), also Europeanization/Europeanisation or occidentalization/occidentalisation (from the Occident, meaning the Western world; see "occident" in the dictionary), is a process whereby societies come under or adopt Western culture in areas such as industry, technology, law, politics, economics, lifestyle, diet, clothing, language, alphabet, religion, philosophy, and values. Westernization has been an accelerating influence across the world in the last few centuries, with some thinkers assuming westernization to be the equivalent of modernization, a way of thought that is often debated. The overall process of westernization is often two-sided in that Western influences and interests themselves are joined with parts of the affected society, at minimum, to change towards a more Westernized society, in the hope of attaining Western life or some aspects of it. To assume, however, Western societies are not affected or changed by this process and interaction with non-Western groups is misleading.