Nearby residents were asked to keep windows closed after firefighters were called to the site of The Bulls Head in Hawes Lane, Rowley Regis shortly after 11pm.
Several small fires were found inside, one in the bar area and another out the back.
Crews from Haden Cross and Oldbury fire stations attended the scene.
A spokesperson for West Midlands Fire Service said: "There were several seats of fire within the derelict property.
"Two hose reels were used, and the gas and electricity were isolated."
Tweeting during the incident shortly before 11.30pm last night, the fire service said: "We currently have two fire appliances from Haden Cross and Oldbury in attendance at a derelict pub fire on the Hawes Lane, in Rowley Regis. Please avoid the area, and if you are from the area please keep your windows closed."
Nobody was found inside the building.