Neff is a surname of German (also Naf, Naef, Kneff), Swiss (also Naff, Naffe, Nafe), Czech or Ashkenazi Jewish origin. Notable people with the surname include:

• Charles D. Neff (1922–1991), American Mormon missionary and humanitarian
• Christophe Neff (born 1964), Franco - German geographer
• Donald Neff (1930–2015), American journalist
• Dorothea Neff (1903–1986), Austrian stage and film actress
• Felix Neff (1798–1829), Swiss Protestant divine and philanthropist
• Francine I. Neff (1925–2010), 35th Treasurer of the United States 1974–77
• Garrett Neff (born 1984), American fashion model
• Henry H. Neff (born 1973), American author and illustrator
• Jacob H. Neff (1830–1909), American politician; lieutenant governor of California 1899–1903
• Jay H. Neff (1854–1915), American newspaper publisher; mayor of Kansas City 1904–05
• Jean-Marie Neff (born 1961), French racewalker
• John Neff (American football) (before 1907–1938), American college football coach
• John Neff (1931–2019), American investment
• Kristin Neff (contemporary), American psychologist
• Leonard Neff (1925–2006), American psychiatrist
• Lucas Neff (born 1985), American actor
• Lyle Neff (born 1969), Canadian poet and journalist
• Marcus Neff (1826–1896), American settler in Oregon; respondent in the U.S. Supreme Court case of Pennoyer v. Neff
• Ondřej Neff (born 1945), Czech science fiction writer and journalist
• Pat Morris Neff (1871–1952), American politician from Texas; governor of Texas 1921–25
• Prudence Neff (1887–1949), pianist and music teacher based in Chicago
• Tom Neff (born 1953), American film executive, director, and producer
• Vladimír Neff (1909–1983), Czech writer and translator
• Wallace Neff (1895–1982), American architect
• Wolfgang Neff (1875–1936), Czech film director