Gun Show Loophole Closing Act of 2015

Amends the federal criminal code to make it unlawful for any person to operate a gun show unless such person: (1) has attained 21 years of age; (2) is not prohibited from transporting, shipping, or receiving firearms and has not violated any federal firearms requirements; (3) has registered with the Attorney General as a gun show operator and has provided a photograph and fingerprints; (4) has not concealed material information nor made false statements in connection with a gun show operator registration; and (5) notifies the Attorney General of the date, time, and duration of a gun show not later than 30 days before the commencement of such show and verifies the identity of each vendor at the gun show.

Imposes recordkeeping requirements on gun show operators and criminal penalties for failure to register as a gun show operator and maintain required records.

Grants the Attorney General authority to enter the business premises of any gun show operator, without a showing of reasonable cause or a warrant, to examine records and inventory to determine compliance with this Act.

Increases criminal penalties for serious recordkeeping violations and violations of criminal background check requirements.

Authorizes the Bureau of Alcohol, Tobacco, Firearms, and Explosives to hire additional investigators to carry out inspections of gun shows.