Thaification, or Thai-ization, is the process by which people of different cultural and ethnic origins living in Thailand become assimilated to the dominant culture of Thailand, that of central Thailand.

Thai people, Chao Phraya Thai, Central Thai people, Southern Thai people, Siamese, Thai Siam, Tai Noi people, are a Southeast Asian ethnic group native to Thailand. In a narrower sense, the Thais are also a Tai ethnic group dominant in Central and Southern Thailand. Part of the larger Tai ethno-linguistic group native to Southeast Asia as well as Southern China and Northeast India, Thais speak the Sukhothai languages, which is classified as part of the Kra–Dai family of languages. The majority of Thais are followers of Theravada Buddhism.