Impressment, colloquially "the press" or the "press gang", is the taking of men into a military or naval force by compulsion, with or without notice. European navies of several nations used forced recruitment by various means. The large size of the British Royal Navy in the Age of Sail meant impressment was most commonly associated with Great Britain and Ireland. It was used by the Royal Navy in wartime, beginning in 1664 and during the 18th and early 19th centuries as a means of crewing warships, although legal sanction for the practice can be traced back to the time of Edward I of England. The Royal Navy impressed many merchant sailors, as well as some sailors from other, mostly European, nations. People liable to impressment were "eligible men of seafaring habits between the ages of 18 and 55 years". Non-seamen were sometimes impressed as well, though rarely. In addition to the Royal Navy's use of impressment, the British Army also experimented with impressment from 1778 to 1780.

Impressment was strongly criticised by those who believed it to be contrary to the British constitution. Though the public opposed conscription in general, impressment was repeatedly upheld by the courts, as it was deemed vital to the strength of the navy and, by extension, to the survival of the British realm and influence.

Impressment was essentially a Royal Navy practice, reflecting the sheer size of the British fleet and its substantial manpower demands. While other European navies applied forced recruitment in times of war, this was generally done as an extension of the practice of formal conscription applied by most European armies from the Napoleonic Wars on. The U.S. Continental Navy also applied a form of impressment during the American War of Independence.

The impressment of seamen from American ships caused serious tensions between Britain and the Thirteen Colonies in the years leading up to the Revolutionary War. One of the 27 colonial grievances enumerated in the Declaration of Independence directly highlights the practice. It was again a cause of tension leading up to the War of 1812. After the defeat of Napoleon in 1815, Britain formally ended the practice; later conscription was not limited to the Royal Navy but covered all British armed forces.