The Stamp Act of 1765 (short title Duties in American Colonies Act 1765; 5 George III, c. 12) was the fourth Stamp Act to be passed by the Parliament of Great Britain but the first attempt to impose such a direct tax on the colonies. The act required all legal documents, permits, commercial contracts, newspapers, wills, pamphlets, and playing cards in the American colonies to carry a tax stamp. It was part of an economic program directly effecting colonial policy that was necessitated by Britain’s greatly increased national debt incurred during the British victory in the Seven Years War (the North American theater of the war was referred to as the French and Indian War).

Britain found it necessary to maintain a significant military presence in North America due to the added defense requirements resulting from the vast new territories acquired during the war and the threat from native Americans in the western frontier exemplified by the outbreak of Pontiac's Rebellion in 1763. The British felt that the colonies were the primary beneficiaries of these military preparations and should pay for at least a portion of the current and future expenses directly incurred in North America. The less controversial (from a colonial standpoint) Sugar Act of 1764 and the Stamp Act were the initial attempts to raise these funds from the colonists. Parliament announced in April of 1764 when the Sugar Act was passed that they would also consider a stamp tax in the colonies. A stamp tax had been an effective and easy to administer source of revenue within Great Britain for years. Although opposition to this possible tax from the colonies was soon forthcoming, there was little expectation in Britain, either by members of Parliament or American agents in Great Britain such as Benjamin Franklin, of the intensity of the protest that the tax would generate. The Stamp Act was passed by a large majority on March 22, 1765, and went into effect later that year on November 1.

Once in effect, the tax met with great resistance in the colonies. For over a century the colonists had insisted on their rights as Englishmen to be taxed only with their consent – consent that was granted only to their colonial legislatures. All colonial assemblies sent petitions of protests and the Stamp Act Congress, reflecting the first significant joint colonial response to any British measure, also petitioned Parliament and the King. Local protest groups, led by colonial merchants and landowners, established connections through correspondence that created a loose coalition that extended from New England to Georgia. Protests and demonstrations initiated by these groups often turned violent and destructive as the masses became involved. Very soon all stamp tax distributors were intimidated into resigning their commissions, and the tax was never effectively collected.

Opposition to the Stamp Act was not limited to the colonies. British merchants and manufacturers, whose exports to the colonies were threatened by colonial economic problems exacerbated by the tax, also pressured Parliament. The Act was repealed on March 18, 1766 as a matter of expedience, but Parliament affirmed its power to tax the colonies “in all cases whatsoever” by also passing the Declaratory Act. This incident increased the colonists' concerns about the intent of the British Parliament and added fuel to the growing movement that became the American Revolution.