Diniz is a Portuguese-language surname. It may refer to:
Denis of Portugal (1261–1325), the sixth King of Portugal and the Algarve Abilio Diniz (1936–2024), Brazilian businessman, father of Pedro Alex Diniz (born 1985), Brazilian cyclist Ângela Diniz (1944–1976), Brazilian socialite Clelio Campolina Diniz (born 1942), Brazilian mechanical engineer Fernando Diniz (born 1974), Brazilian football coach Gabriel Diniz (1990–2019), Brazilian singer and composer Jacinto F. Diniz (1888–1949), American politician Leila Diniz (1945–1972), Brazilian actress Mauro Diniz (born 1952), Brazilian cavaquinist and singer Paulo Diniz (1940–2022), Brazilian singer Paulo Roberto Diniz Jr. (fl. 1990s–2010s), Brazilian bass guitarist Pedro Diniz (born 1970), Brazilian racing driver, son of Abílio Priscillo Diniz (born 1948), Brazilian golfer Renan Diniz (born 1993), Brazilian footballer Renata Diniz (born 1985), Brazilian footballer Renata Diniz (gymnast) (born 2008), Brazilian rhythmic gymnast Yohann Diniz (born 1978), French race walker