Guglielmi is an Italian surname that may refer to Alejandro Guglielmi (born 1936), Argentine equestrian Alighiero Guglielmi (1912−1988), Italian racewalker Éric Guglielmi (1970–2021), French photographer, editor, and photojournalist Gary Guglielmi (born 1958), Australian speedway hider Gregorio Guglielmi (1714−1773), Italian-born fresco painter who worked primarily in Germany Louis Guglielmi (1916–1991), Spanish-born French musician Marco Guglielmi (1926–2005), Italian actor, screenwriter and author Massimo Guglielmi (born 1970), Italian lightweight rower Monica Guglielmi (born 1974), Italian former professional tennis player Noel Gugliemi, American actor O. Louis Guglielmi (1906–1956), American artist Pietro Alessandro Guglielmi (1728–1804), Italian opera composer (father of Pietro Carlo Guglielmi) Pietro Carlo Guglielmi (1772–1817), Italian opera composer Ralph Guglielmi (1933–2017), American football quarterback Simon Guglielmi (born 1997), French cyclist Rodolfo Alfonso Raffaello Piero Filiberto Guglielmi (1895–1926), known as Rudolph Valentino, Italian actor based in the US