De Ridder is a Dutch surname, meaning "the knight". It may refer to:
People Alexandra Simons de Ridder (born 1963), German equestrian Alfons de Ridder (1882–1960), Flemish writer and poet Allard de Ridder (1887–1966), Dutch and Canadian conductor, violist, and composer André de Ridder (born 1971), German music conductor Chantal de Ridder (born 1989), Dutch footballer Daniël de Ridder (born 1984), Dutch footballer Daniela De Ridder (born 1962), German politician Dirk de Ridder (sailor) (born 1972), Dutch competitive sailor Gaspard Deridder (1918–1977), Belgian boxer Hilde De Ridder-Symoens (1943–2023), Dutch historian Johan de Ridder (1927–2013), South African architect Louis De Ridder (1902–1981), Belgian winter sports athlete Luis de Ridder (1928–2004), Argentine alpine skier Marcello de Ridder (1922–1973), Argentine bobsledder Minneke De Ridder (born 1980), Belgian politician (born 1948), Belgian historian and politician Peter de Ridder (born 1946), Dutch businessman and sailor Philippe De Ridder (born 1964), Belgian football player, coach, and administrator Reinier De Ridder (born 1990), Dutch mixed martial artist Steve De Ridder (born 1987), Belgian footballer Willem de Ridder (1939–2022), Dutch artist and anarchist Jäger de Ridder (born 2007), Aspiring mixed martial artist
Other DeRidder, Louisiana, a place named for Ella de Ridder, the sister-in-law of a Dutch railroad financier