More than 450 tourists and residents, from two hotels and 92 houses, were moved out, while 60 officers scoured the area for those who refused to leave, local police said.
Greece’s fire service was fighting three other major blazes across the country but in Lesbos the danger was more acute.
More than five hours after the first emergency call was made, the evacuation process was continuing, fire service spokesman Yannis Artopoios said.
Fifty firefighters used 17 fire engines, nine special planes and one helicopter to contain the blaze.
The wildfire broke out at 10am on Saturday and was burning on two fronts — towards Vrisa village and within Vatera.
West Lesbos mayor Taxiarchis Verros ordered the evacuation as a precautionary measure, acting on the advice of the fire brigade.
The biggest fire burning in the country is in the north-east, near the border with Τurkey and inside a national forest that is the home to rare species, such as vultures. The Dadia national forest is mostly made up of highly flammable pine trees.
Officials said 320 firefighters in 68 fire engines, plus six special planes, nine helicopters and many volunteers were fighting the inferno, while 200 lumberjacks were cutting firebreak paths through the forest.
Two more major fires were burning in the area, one in a remote mountainous area in the Greek region of Western Macedonia and another in the southern Peloponnese, Mr Artopoios said.