Ridder may refer to:

Places

• DeRidder, Louisiana, city in US state of Louisiana
• Ridder, Kazakhstan, settlement in Kazakhstan (named for Philip Ridder)

Things

• Ridder (title), Dutch and Belgian title equivalent to knight
• Knight Ridder, newspaper chain
• Arbeidets Ridder, US newspaper (1880s), published in Minneapolis, Minnesota (Norwegian/Danish language; concerning news of interest to labor groups)
• Ridder Arena, an ice hockey arena in Saint Paul, Minnesota

People

• Alexandra Simons de Ridder (born 1963), German equestrian
• Bernard J. Ridder (1913–1983), American newspaper publisher
• Daniël de Ridder (born 1984), Dutch football player
• Desmond Ridder (born 1999), American football player
• Eric Ridder (1918–1996), US sailor and Olympic athlete
• Georgia B. Ridder (1914–2002), American thoroughbred racehorse owner
• Herman Ridder (1851–1915), American newspaper publisher and editor
• Kathleen Ridder (1922–2017), American activist and philanthropist
• Koen Ridder (born 1985), Dutch badminton player
• Louis De Ridder (1902–1981), Belgian winter sports athlete
• Luis de Ridder (1928–2004), Argentine alpine skier
• Marcello de Ridder (1922–1973), Argentine bobsled athlete
• Marjan Ridder (born 1953), Dutch badminton player
• Peter de Ridder (born 1946), Dutch sailor and businessman
• Peter Hollander Ridder (1608–1692), Governor of New Sweden
• Philip Ridder (1759–1838), English explorer who discovered valuable metal ores in Kazakhstan
• Robert Ridder (1919–2000), American ice hockey administrator, media mogul
• Steve De Ridder (born 1987), Belgian football player
• Victor F. Ridder (1886–1963), American newspaper publisher