The blaze broke out in the kitchen of the property in Corporation Street at around 8-45am.
Two fire engines from Clitheroe and Hyndburn attended the scene.
Firefighters used two breathing apparatus, one hose reel and a ventilation unit to extinguish the fire.
Smoke from the fire affected neighbouring properties but no injuries were reported.
Clitheroe Fire tweeted: “The importance of working smoke alarms proved themselves this morning at a house in Clitheroe.
“Luckily the occupants got out and called for us. Unfortunately the occupants doesn’t [sic] have contents insurance.”