HM Customs (His or Her Majesty's Customs) was the national Customs service of England (and then of Great Britain from 1707, the United Kingdom from 1801) until a merger with the Department of Excise in 1909. The phrase 'HM Customs', in use since the Middle Ages, referred both to the customs dues themselves and to the office of state established for their collection, assessment and administration.

The payment of customs duty (i.e. a levy on imported or exported goods) has been recorded in Britain for well over a thousand years. A centralised system for their collection has been in place since the 13th century, overseen since the 17th century by a Board of Commissioners (the Board of Customs). In 1909, HM Customs was merged with the Excise department (responsible for raising revenue from inland taxes) to create HM Customs and Excise (HMCE), responsible for all forms of indirect taxation. Just under a century later, HMCE was itself merged with the Inland Revenue (responsible for direct taxation) to create HM Revenue and Customs.