The fire at the property in Hamnavoe broke out shortly after 6am this morning. Four crews were involved in putting out the fire, which was extinguished after about three hours.
There are not thought to be any casualties as a result of the blaze, at an unspecified location near the B9074 road. Highlands and Islands Fire and Rescue Service said the crews remained at the scene.
Meanwhile, a 79-year-old woman was treated for smoke inhalation following a flat fire in Edinburgh.
Emergency services were called to the ground-floor property in the city's North Junction Street at 7.42pm last night.
Lothian and Borders Fire and Rescue Service said: "One female casualty suffering from smoke inhalation was treated at the scene but didn't go to hospital."