West Yorkshire Police were called to the house on Smith Crescent at 6pm last night (Mon Dec 18) following a report of a "concern for safety" incident.
A police cordon remains in place outside the house, which were split into separate flats, as the investigation continues.
A West Yorkshire Police spokesman said: "The deaths are being treated as unexplained."
Neighbour Joanne Hayes said: "I think she had lived there about two years. She was a lovely lass, I don't know what happened."
Another neighbour, Barbara Francis, said: "It's really sad, she was a nice girl and always said 'hello'."
West Yorkshire Fire and Rescue Service said: "Fire crews were called to a property in Smith Crescent, Rastrick, Brighouse, at 19.30 hrs on December 18.
"Fire engines from Rastrick and Huddersfield attended. A fire at the property was confirmed out on arrival of crews.
"The bodies of a man and woman were found inside the property.
"A fire investigation officer attended the scene today to look into the circumstances around the fire.
"West Yorkshire Fire and Rescue Service is working alongside West Yorkshire Police as enquiries continue.
"At this time, the deaths are being treated as unexplained."