Muniz or Muñiz is a surname, and may refer to:
- Aned Y. Muñiz Gracia, a professor
- Carlos Muñiz (born 1981), a baseball player
- Frankie Muniz (born 1985), an American actor
- Júlio César de Paula Muniz Júnior (born 1988), a Brazilian football player
- Manny Muñiz (born 1947), a Puerto Rican baseball player
- Marco Antonio Muñiz (born 1933), a Mexican singer
- Marc Anthony (born 1968), a Puerto Rican singer (born Marco Antonio Muñiz)
- Nicole Muñiz (1987-2003), an innocent bystander in a sniper shooting
- Rafo Muñiz (born 1956), a Puerto Rican actor, director, & producer
- Tomás Muñiz (1900-1965), a Puerto Rican radio and television producer
- Tommy Muñiz (born 1922), a Puerto Rican comedian
- Vik Muniz (born 1961), an avant-garde artist