The Boston Port Act is an Act of the Parliament of Great Britain (citation 14 Geo. III. c. 19) which became law on March 31, 1774, is one of the measures (variously called the Intolerable Acts, the Punitive Acts or the Coercive Acts) that were designed to secure Great Britain's jurisdictions over her American dominions.

A response to the Boston Tea Party, it outlawed the use of the Port of Boston for "landing and discharging, lading or shipping, of goods, wares, and merchandise" until such time as restitution was made to the King's treasury (for customs duty lost) and to the East India Company for damages suffered.

In other words, it closed Boston Port to all ships, no matter what business the ship had.

Laws leading to the American Revolution | 1774 in law | Acts of the Parliament of Great Britain