Gainsborough Dupont was a British artist, the nephew and pupil of Thomas Gainsborough, R.A..

Dupont was born in Sudbury, Suffolk, on 20 December 1754 the eldest son of Thomas Gainsborough's sister Sarah, and her husband Philip Dupont. In 1772 he was apprenticed to Gainsborough, for whom he continued to work until the latter's death in 1788. He was the only assistant Gainsborough is ever known to have employed. He also trained at the Royal Academy Schools, where he became a student in March 1775.

Dupont took over Gainsborough's studio in Schomberg House in 1788, and moved to Bloomsbury in 1793, following the death of Gainsborough's widow. He painted portraits and landscapes in a style of similar to that of his uncle, and also landscapes with architectural ruins, in which he imitated Nicolas Poussin. His principal work is a large picture containing the portraits of the elder brethren of Trinity House, which is in their court-room on Tower Hill.