According to West Sussex Fire and Rescue Service, crews were alerted at 12.26pm to reports of a fire at property in Bursledon Close.
Two pumps from Bognor Regis and one from Littlehampton are on scene, the fire service said.
A spokesman said: “Upon arrival, [crews] found a fire in the roof space of the property. Crews brought the fire under control using two high pressure hose reels, one covering jet and one safety jet. Firefighters also used six sets of breathing apparatus.
“Firefighters remained at the scene damping down and turning over, and used a thermal imagine camera to identify any hotspots.
“The last appliance left the scene at 2.34pm.”
Whilst the incident was ongoing, the fire service asked nearby residents to ‘keep your windows and doors closed’.