Sainz is a surname. Notable people with the surname include:
Adolfo Fernández Sainz (born 1947), Cuban journalistBernard Sainz (born 1943), unlicensed sports doctor who achieved success in horse racing and cyclingCarlos Sainz (born 1962), Spanish rally driverCarlos Sainz Jr. (born 1994), Spanish racing driver, son of Carlos SainzFaustino Sainz Muñoz (born 1937), Spanish prelate of the Roman Catholic ChurchGustavo Sainz (born 1940), Spanish language author from MexicoInés Sainz (born 1978), Mexican journalistInés Sáinz Esteban, Spanish beauty pageantJosé Sáinz Nothnagel (1907–1984), Falangist, early leader Spanish Civil WarLolo Sainz (born 1940), Spanish former basketball player and coachRegino Sainz de la Maza (1896–1981), Spanish classical guitaristSeveriano Sainz y Bencamo (1871–1937), the second Bishop of the Roman Catholic Diocese of Matanzas (1915–1937)