Officers were made aware of the blaze, in the St Colm's Quadrant area of Longhope, at around 9.30am today.
A spokesperson for Police Scotland said: "We can confirm that a man has died following a fire at a property on the island of Hoy in Orkney.
"The fire was extinguished by the Scottish Fire and Rescue Service but sadly the body of a man was found inside.
The man's next of kin has been made aware.
Detective Inspector Scott Macdonald added: "Our thoughts are with the man's family and friends at this difficult time for them.
"Enquiries are now ongoing to establish the full circumstances and we are working with the Scottish Fire and Rescue Service.
"This investigation is at an early stage but there are no apparent suspicious circumstances."
A report will now be submitted to the Procurator Fiscal.
Anyone who has information which could help our enquiry is asked to contact Police Scotland on 101, quoting incident 835 of June 12.