Fire crews from across West Yorkshire attended the fire at Lofthouse Hill Golf Club on Leeds Road, Wakefield on Tuesday (June 1).
The fire gutted 80% of the disused building as six pumps were used to contain the blaze.
Photographs show significant damage to the windows and roof of the building.
An aerial pump was also used, West Yorkshire Fire and Rescue Service said.
The aerial appliance and three large jets were used to extinguish the fire.
Appliances attended from Wakefield, Rothwell, Hunslet, Normanton, Ossett and an aerial and support pump from Leeds.
West Yorkshire Police now said they are treating the incident as an arson investigation.
A spokesperson for the force said: "It is being treated as arson.
"Any witnesses are asked to call police on 101 quoting log 0204 of Tues 1 June."