Four crews were called to Hartlebury Common in Stourport-on-Severn at about 8.10pm on Tuesday and found 12 hectares of common land well alight.
Hereford and Worcester Fire and Rescue Service said firefighters extinguished the blaze using a main jet, a hosereel jet, backpacks and beaters.
Crews remained at the scene this morning to continue dampening down. A large area of the reserve stands blackened by fire damage.
A spokesman from the fire service said: "Four Hereford & Worcester Fire and Rescue Service crews – one from Worcester, two from Wyre Forest and one from Kingsland – plus the Landrover from Malvern and the water carrier from Leominster were called at 8.08pm on Tuesday to a fire in the open at Hartlebury Common, Stourport.
"Twelve hectares of common land were well alight and the incident was sectorised with the fire fought using a main jet, a hosereel jet, backpacks and beaters.
"Water was supplied from a hydrant and a dam from the water carrier.
"The service drone was also deployed to survey the fire.
"Crews remain in place this morning using a main jet and backpacks to continue the dampening down operation."