HMS Madagascar was a 46-gun fifth-rate Seringapatam-class frigate, built at Bombay and launched on 15 November 1822.

Madagascar delivered Bavarian Prince Otto, who had been selected as the King of Greece, to his new capital Nafplion in 1833.

In 1843, Madagascar was assigned to suppress the slave trade, which was illegal in Britain.

Operating off the west African coast, it successfully detained the Portuguese slave schooner Feliz in 1837, the Brazilian slave ships Ermelinda Segunda (detained 1842), Independencia (1843), Prudentia (1843) and Loteria (1843), and the Spanish slave brigantine Roberto (1842), along with two other vessels of which the nationalities were not recorded.

This article about a specific naval ship or boat of the United Kingdom is a stub.