|Language(s)||Chinese, Vietnamese, Meitei, others|
Loi may be the spelling of three Chinese surnames, based on their pronunciation in different varieties of Chinese; they are listed below by their spelling in Hanyu Pinyin, which reflects the Mandarin Chinese pronunciation:
- Léi (Chinese: 雷), meaning "lightning"; the spelling Loi is based on the Cantonese pronunciation (Jyutping: Leoi4; Cantonese Yale: Lèuih). The spelling Loi is common in Macau, while other spellings of the same surname such as Lui and Louie are found in Hong Kong and among overseas Chinese.
- Lǚ (traditional Chinese: 呂; simplified Chinese: 吕); nearly-homophonous with the above in Cantonese (Jyutping: Leoi5; Cantonese Yale: Léuih; note the differing tone), and so also spelled Loi, Lui, or Louie.
- Lí (Chinese: 黎), a fossil word meaning "black" or "brown". The spelling Loi is based on the pronunciation in various dialects of Southern Min (e.g. Teochew Peng'im: loi⁵; IPA: /loi˥/)
Loi may also be a Greek surname.
According to statistics cited by Patrick Hanks, there were 282 people on the island of Great Britain and one on the island of Ireland with the surname Loi as of 2011. There was one person with the surname Loi on the island of Great Britain in 1881.
The 2010 United States Census found 1,357 people with the surname Loi, making it the 19,814th-most-common name in the country. This represented an increase from 985 (23,922nd-most-common) in the 2000 Census. In both censuses, slightly fewer than nine-tenths of the bearers of the surname identified as Asian, and between six and eight per cent as White. It was the 1,056th-most-common surname among respondents to the 2000 Census who identified as Asian.
- Francesco Loi (1891–1977), Italian gymnast from Cagliari, Sardinia
- Loi Ah Koon (黎亞坤; fl. 1926–?), Hainan-born founder of the Singapore-based Ya Kun Kaya Toast café chain
- Duilio Loi (1929–2008), Italian boxer
- Loi Wai Long (雷偉隆; born 1989), Macau football defender
- Cleo Loi (born c. 1991), Australian astrophysicist
- Loi Wai Hong (雷偉洪; born 1992), Macau football defender
- Antonio Loi (born 1996), Italian football midfielder from Isili, Sardinia
- Livio Loi (born 1997), Belgian motorcycle racer
- Loi Im Lan (呂艷蘭; born 1998), Macau sprinter
- Hanks, Patrick; Coates, Richard; McClure, Peter, eds. (2016). The Oxford Dictionary of Family Names in Britain and Ireland. Oxford University Press. p. 1614. ISBN 9780192527479.
- Fielde, Adele M. (1883). "黎". A pronouncing and defining dictionary of the Swatow dialect, arranged according to syllables and tones. Shanghai: American Presbyterian Mission Press. p. 361.
- Hanks, Coates & McClure 2016, p. 1614, entry #3. Also "雷". Nom Foundation. Retrieved 22 November 2018.
- Hanks, Patrick (2003). Dictionary of American Family Names. Oxford University Press. p. 455. ISBN 0199771693.
- "Diffusione del cognome Loi". Mappe dei Cognomi Italiani. Retrieved 24 November 2018.
- "How common is your last name?". Newsday. Retrieved 5 September 2018.
- "Most common last names for Asians and Pacific Islanders in the U.S." Mongabay. Retrieved 8 January 2018.