Guglielmo (pronounced [ɡuʎˈʎɛlmo]) is the Italian form of the masculine name William. It may refer to:
People with the given name Guglielmo:
Guglielmo I Gonzaga (1538–1587), Duke of Mantua and Montferrat
Guglielmo Agnelli (c. 1238 – 1313), Italian sculptor and architect
Guglielmo Arena (born 1973), Swiss football manager
Guglielmo Bergamasco (c. 1485 – 1550), Italian architect
Guglielmo Borremans (1670–1744), Baroque painter
Guglielmo Bosca (born 1993), Italian alpine skier
Guglielmo Caccia (1568–1625), Italian painter
Guglielmo Achille Cavellini (1914–1990), influential Italian art collector and mail artist
Guglielmo da Leoni (c. 1664 – 1740), Italian painter and engraver
Guglielmo da Marsiglia (1475–1537), Italian painter of stained glass
Guglielmo della Porta (c. 1500 – 1577), Italian architect and sculptor
Guglielmo della Scala (died 1404), Lord of Verona
Guglielmo Ebreo da Pesaro (c. 1420 – c. 1484), Italian dancing-master
Guglielmo Embriaco (born c. 1040), Genoese merchant and military leader
Guglielmo Ferrero (1871–1942), Italian historian, journalist and novelist
Guglielmo Fiammingo (c. 1530 – 1587), sculptor
Guglielmo Fieschi (13th century), Italian cardinal
Guglielmo Gabetto (1916–1949), Italian former football (soccer) player
Guglielmo il Giuggiola (16th century), Italian poet
Guglielmo Letteri (1926–2006), Italian comic book artist
Guglielmo Libri Carucci dalla Sommaja (1803–1869), Italian mathematician
Guglielmo Marconi (1874–1937), Italian inventor
Guglielmo Massaia (1809–1889), Italian Catholic missionary
Guglielmo Nasi (1879–1971), Italian General
Guglielmo Oberdan (1858–1882), Italian irredentist and terrorist
Guglielmo Pallotta (1727–1795), Italian Roman Catholic Cardinal
Willie Pep (1922–2006), real name Guglielmo Papaleo, American professional boxer
Guglielmo Pepe (1783–1855), Italian general and patriot
Guglielmo Plüschow (1852–1930), German photographer
Guglielmo Quarenghi (1826–1882), Italian composer
Guglielmo Sanfelice d'Acquavilla (1834–1897), cardinal of the Roman Catholic Church
Guglielmo Scheibmeier (born 1924), Italian bobsledder
Guglielmo Stendardo (born 1981), Italian football defender
Guglielmo Verdirame, Baron Verdirame (born 1971), Italian-born British lawyer and member of the House of Lords
Guglielmo Vicario (born 1996), Italian footballer
Guglielmo Visconti (c. 1210 – 1276), Italian cardinal
Mastro Guglielmo (fl. 12th century), Italian painter
Niccolò Guglielmo Alforae, French engraver
William Guglielmo Niederland (1904–1993), German-American psychoanalyst
People with the surname Guglielmo:
Augie Guglielmo (1915–1996), American baseball umpire
Dudley A. Guglielmo (1909–2005), American insurance commissioner
Tony Guglielmo (born 1940), American senator