Firefighters from Normanton and Castleford were called to the home on Heseltine Close, Normanton, at around 12.20pm on Sunday.
Watch Commander at Castleford David Smith said: “Nobody was in the house at the time. When the occupants returned, they found the house full of smoke and there was quite an intense fire in the living room.
“It is believed the lights on the Christmas tree, which were possibly faulty, had caused the blaze.
“We would urge people not to leave their tree lights switched on when not in the property.”