Nieto (“grandchild”) is a Spanish surname, Neto is the Portuguese version of the name. Notable people with the surname include:

• Alfonso Nieto (born 1991), Mexican footballer
• Alfonso Nieto Castañón (born 1972), Spanish neuroscientist
• Alfredo Diez Nieto (1918-2021), Cuban composer and centenarians
• Amalia Nieto (1907–2003), Uruguayan painter, sculptor, and engraver
• Ángel Nieto (1947–2017), Spanish motorcycle racer
• Antonio Jesús López Nieto (born 1958), Spanish football referee
• Carlos Nieto, multiple people of the same name
  • Carlos Nieto (rugby union) (born 1976), Italian rugby union player
  • Carlos Nieto (footballer) (born 1996), Spanish footballer
• Claudio Nieto Jiménez (born 1977), Chilean ski mountaineer and triathlete
• Daniel Nieto Vela, (born 1991), Spanish footballer
• David Nieto (1654–1728), Jewish Hakham in London
• Domingo Nieto (1803–1844), President of Peru
• Enrique Peña Nieto (born 1966), President of Mexico
• Enrique Nieto (architect) (1880 or 1883–1954), Spanish architect
• Ernesto Nieto (born 1940), founder of the National Hispanic Institute
• Federico Nieto (born 1983), Argentine footballer
• Fonsi Nieto (born 1978), Spanish motorcycle racer
• Jamie Nieto (born 1976), American high jumper
• Jan Nieto (born 1981), Filipino singer
• José Nieto (composer) (born 1942), Spanish musician and composer
• José Javier Palomo Nieto, Salvadoran politician
• Juan José Nieto Gil, (1805–1866), 61st president of Colombia
• John Marvin Nieto (born 1977), Filipino actor and politician better known by his screen name Yul Servo
• Johnielle Keith "Kit" Nieto (born 1969), Filipino lawyer and politician
• Manuel Nieto (1734–1804), soldier in Spanish California
• Matt Nieto (born 1992), American ice hockey player
• Miguel Ángel Nieto (born 1986), Spanish soccer player
• Pablo Nieto (born 1980), Spanish motorcycle racer
• Rafael Nieto Navia (born 1938), Colombian jurist
• Rey Joseph "RJ" Nieto (born 1985), Filipino blogger and opinion columnist also known as Thinking Pinoy
• Rodolfo Nieto (1936–1985), Mexican painter
• Tom Nieto (born 1960), American baseball player and manager
• Victor Nieto (1916–2008), founder and director of the Cartagena Film Festival