The house on Bucknell Circuit in Isabella Plains was extensively damaged but no one was believed to injured.
Police said that about 10.15 am on Friday, members of the public saw the Isabella Plains residence on fire and contacted emergency services.
The scene was declared safe around 2 pm and handed over to ACT Policing to investigate the circumstances surrounding the blaze.
Police are urging anyone who may have any information that could assist police to contact Crime Stoppers on 1800 333 000, or via the Crime Stoppers ACT website.
