Stamp Acts, laws for the raising of revenue by requiring the use of government stamps on the paper or parchment by means of which business is transacted or privileges conferred, or upon packages of goods put up for sale, etc. Such laws were introduced into England, in the reign of William and Mary, from Holland, and from that time to the present have been a favorite mode of raising revenue. Each stamp represents a tax of a certain sum which must be paid to obtain it, and its payment is enforced by imposing penalties on those who undertake to evade the tax, and by declaring the transaction in which it should have been made use of invalid if the stamp is not obtained and used. The name of stamp act was made odious in America by the attempt in 1765 to tax the colonies in this form; but after the Union was perfected by means of the constitution a few stamp duties were for a time laid. During the civil war of 1861-5 stamp taxes were laid on almost every form of legal instrument, bank drafts and checks, conveyances of land, etc, and on the packages of a great variety of manufactured goods.

Many of these have since been taken off, but the stamp taxes on manufactures are generally retained. (See Taxes).