Cantonese, or Standard Cantonese, is a language that originated in the vicinity of Canton (i.e. Guangzhou) in southern China, and is often regarded as the prestige dialect of Yue Chinese.

In mainland China, it is a lingua franca in Guangdong Province and some neighbouring areas, such as the eastern part of Guangxi Province. Outside mainland China, it is spoken by the majority population of Hong Kong and Macau in everyday life. It is also spoken by overseas Chinese communities in Southeast Asia (like Singapore and Christmas Island), the United States, Canada, Brazil, Peru, Cuba, Panama, Australia, and New Zealand, as well as parts of Europe, and is the most widely spoken non-Mandarin Sinitic language in the world.

While the term "Cantonese" refers narrowly to the prestige dialect described in this article, it is often used in a broader sense for the entire Yue branch of Chinese, including related dialects such as Taishanese.

The Cantonese language is also viewed as part of the cultural identity for the native speakers across large swathes of southern China, Hong Kong and Macau. Although Cantonese shares much vocabulary with Mandarin Chinese, the two languages are not mutually intelligible largely because of pronunciation and grammatical differences. Sentence structure, in particular the placement of the verb, sometimes differs between the two languages. The use of vocabulary in Cantonese also tends to have more historic roots. The most notable difference between Cantonese and Mandarin is how the spoken word is written; with Mandarin the spoken word is written as such, where with Cantonese there may not be a direct written word matching what was said. This results in the situation in which a Mandarin and Cantonese text almost look the same, but both are pronounced differently.