Firefighters were called to the blaze at the old Fate club in High Street at about 4pm on Sunday.
Five appliances attended the fire which caused significant damage to the building, which had been The Feathers pub for many years before it became Fate.
A spokesman for Northants Police said: “A 15-year-old was arrested by Northamptonshire Police on suspicion of arson and later released under investigation.”
Anyone with any information about the fire can call Northamptonshire Police on 101 or Crimestoppers, in confidence, on 0800 555111.
