Officials believe the blaze, which started late on Monday, was started deliberately on Monte Mario, which lies between the Tuscan art cities of Pisa and Lucca.
Local authorities said some 700 people were told to leave their homes as a precaution in the towns of Calci and Vicopisano, while schools in the area were all shut. There were no immediate reports of injuries or of damage to properties.
Some 600 hectares of woodland were destroyed and a large cloud of smoke cast a pall over Pisa. The city's airport said it would shut to commercial traffic until 7.40 p.m. (1540 GMT) "to help firefighters engaged in extinguishing the blaze".
Two Canadair aircraft and four helicopters crisscrossed the skies, dumping thousands of litres of water on the fires, which were fanned by strong winds.
