Fierro is a Spanish and Italian surname meaning "iron".
Fierro may also refer to:
- Martín Fierro, a fictitious character in a poem by Argentine José Hernández
- See also Martín Fierro (disambiguation)
- Fanny Carrión de Fierro, Ecuadorean writer and literary critique
- Fierro (film), an Argentinian animated film released November 2007
- Gonzalo Fierro (born 1983), Chilean football player
- Josefina Fierro de Bright (1914–1998), Mexican-American activist
- Juan Fierro (born 1974), Chilean road cyclist
- Luis Fierro (born 1964), Ecuadorean economist and social development specialist
- Martha Fierro (born 1977), Ecuadorean chess champion
- Martin Fierro (saxophonist) (1942–2008), saxophonist
- Rodrigo Fierro, Ecuadorean M.D., writer and politician, former Minister of Health of Ecuador.
- Fierro Group, a Spanish economic group
- San Fierro, San Andreas, a fictional city
- Aurelio Fierro (1923–2005), an actor and singer of the Neapolitan dialect in Naples, Italy. Famous for his song, "À pizza."