Four fire engines went to the scene in Reidhaven Square, Keith, when the alarm was raised just after 9pm on Thursday.
Police said that one male died following the fire in the residential property, which was brought under control by 10pm.
They have launched a joint investigation with the Scottish Fire and Rescue Service (SFRS).
A police spokesman said: “Inquiries are at an early stage and police are working with SFRS to investigate the circumstances.”
Some local roads were closed while emergency services dealt with the incident.