The British half crown was a denomination of sterling coinage worth 1⁄8 of one pound, or two shillings and six pence (abbreviated "2/6", familiarly "two and six"), or 30 (old) pence. The half crown was first issued in 1549, in the reign of Edward VI. No half crowns were issued in the reign of Mary, but from the reign of Elizabeth I half crowns were issued in every reign except that of Edward VIII, until the coins were discontinued in 1970.

The half crown was demonetised (ahead of other pre-decimal coins) on 1 January 1970, the year before the United Kingdom adopted decimal currency on Decimal Day. During the English Interregnum of 1649–1660, a republican half crown was issued, bearing the arms of the Commonwealth of England, despite monarchist associations of the coin's name. When Oliver Cromwell was made Lord Protector of England, half crowns were issued bearing his portrait depicting him wearing a laurel wreath in the manner of a Roman Emperor. The half crown did not display its value on the reverse until 1893. In the 20th century a slang term for the coin was "half-a-dollar".