Sir Benjamin Hammet (c. 1736 – 22 July 1800) was an English businessman, banker and politician, who served as Member of Parliament from Taunton (1782–1800), and as High Sheriff of London.

Contemporary accounts state that he was a footman, son of a Taunton barber, who courted and married Louisa Esdaile, the sister-in-law of his master John 'Vulture' Hopkins. Louisa was the daughter of Sir James Esdaile, a rich banker; and Hammet's success as a banker and building contractor was credited to the influence and funding provided by his father-in-law, who on the occasion of their marriage settled £5,000 on the bride. ^[1]

Hammet was elected as Lord Mayor of London (a title which his father-in-law had held previously) in 1797, but paid a £1,000 penalty rather than serve (pleading ill health). He died 22 July 1800 at Castle Maelgwyn, his Welsh estate. Upon his death, his son John Hammet succeeded him as M.P., and would hold that seat until his own death in 1811.^[2]