923) is legislation enacted by the United States Congress to prevent the incurring of obligations or the making of expenditures (outlays) in excess of amounts available in appropriations or funds.

Many agencies, particularly the military, would intentionally run out of money, obligating Congress to provide additional funds to avoid breaching contracts.

[2][3] The act provided: ... that it shall not be lawful for any department of the government to expend in any one fiscal year any sum in excess of appropriations made by Congress for that fiscal year, or to involve the government in any contract for the future payment of money in excess of such appropriations.

To some extent, but not entirely, it implements the provisions of Article One of the United States Constitution, Section 9, Clause 7 (the "power of the purse"), which provides that "No money shall be drawn from the treasury, but in consequence of appropriations made by law."

The Government Accountability Office, inspectors general, and individual agencies investigate potential violations of the Antideficiency Act every year.

[7] However, agreements have been changed and reported due to ADA violations,[8] and punitive administrative actions are routinely taken against government employees.

[9] The ADA is cited as the reason for a government shutdown when Congress misses a deadline for passing an interim or full-year appropriations bill.