The Utsuls ([hu˩ t͡saːn˧˨]; traditional Chinese: 回輝人; simplified Chinese: 回辉人; pinyin: Huíhuī rén) or (Chinese: 海南回族; pinyin: Hǎinán huízú) are an ethnic group which lives on the island of Hainan, China, and are considered one of the People's Republic of China's undistinguished ethnic groups. They are found on the southernmost tip of Hainan near the city of Sanya. According to the traditions of the Utsuls, their ancestors were Muslims who migrated southward out of Central Asia into their present day location. However, they are thought to be descendants of Chamrefugees who fled their homeland in what is now southern Vietnam to escape from Vietnamese invasion. After the Vietnamese completed the conquest of Cham, sacking Vijaya, the capital of Champa, a Cham Prince and some 1,000 Cham moved to Hainan, where the Ming dynasty allowed them to set up an exile kingdom. Several Chinese accounts record Cham arriving on Hainan even earlier, from 986, when the Cham capital fell in 982, several Cham fled to Hainan during the Song dynasty. After the 982 fall of the capital Indrapura to Vietnam, some Cham fled to Guangzhou in addition to Hainan.
While most of the Chams who fled Champa went to neighbouring Cambodia, a small business class fled northwards. How they came to acquire the name Utsul is unknown.
Although they are culturally distinct from their neighbours, the Chinese government places them as members of the Hui nationality. However, from reports by Hans Stübel, the German ethnographer who "discovered" them in the 1930s, their language is completely unrelated to any other language spoken in mainland China. About 3,500 of them are speakers of the Tsat language, which is one of the few Malayo-Polynesian languages that are tonal. Whereas other Hui people are Muslims who do not have a mother tongue or traditional ethnic language distinct from the Sinitic dialects, the Utsuls do have their own language, which is regarded as separate and distinct from Sinitic dialects. As a result, their classification as Hui people is controversial.