Giovanni di Vico (died 1366) was an Italian Ghibelline leader, lord of Viterbo, Vetralla, Orvieto, Narni and numerous other lands in northern Lazio and Umbria.
Giovanni was named Imperial vicar of Latium by emperor Louis IV of Bavaria, confirmed in 1342 by Pope Clement VI.
After a short reconciliation, in 1347 Cola di Rienzo, senator of Rome, declared Giovanni a rebel and waged war against him.
He thenceforth continued his ruthless policy of ravages against the Papal territories, refusing always to present himself in Avignon to respond for his deeds.
He was also initially victorious against Gil de Albornoz, the skillful Cardinal sent by Pope Innocent VI to conquer back the usurped territories of the Papal States, but in 1354 he was decisively defeated near Orvieto.