Guglielmo Marconi
1st Marquis of Marconi, Italian inventor of radio
Guglielmo Ciro Nasi
Italian WWII general
Guglielmo Palazzani
Italian rugby union player
Guglielmo Pepe
Italian general and patriot
Guglielmo Caccia aka il Moncalvo
Italian painter
Guglielmo Scheibmeier
Italian bobsledder