Named after Great Portland Street, which honours the Dukes of Portland.
The land came to them in 1734, when the Harley heiress Lady Margaret Cavendish Harley married the 2nd Duke of Portland. The street long had two names: John Street near Oxford Street, first rated in 1726, and Portland Road at the north end. The station opened in 1863 as Portland Road and became Great Portland Street in 1917.