Britain's Froome got help from Sky Procycling teammates Peter Kennaugh and Richie Porte on the grueling final climb of the 150-mile stage, the longest of the race, clearly outdistancing the field on Mont Ventoux.
His performance over the final 13-mile climb allowed him to finish at 5 hours, 48 minutes, 45 seconds, easily besting Colombia's Nairo Quintana by 29 seconds.
Froome notched his third overall stage victory and second of the 2013 race, extending his overall lead by nearly 2 minutes over Dutchman Bauke Mollema and two-time Tour champ Alberto Contador of Spain.
He now holds a 4:14 lead over Mollema, who finished eighth Sunday, while Contador fell 4:25 behind.
The Briton appeared poised for a victory as the race headed into Monday's rest day.