John Samuel Agar (1773–1858) was an English portrait painter and engraver, who exhibited his works at the Royal Academy from 1796 to 1806[1] and at the British Institution until 1811. He did not exhibit again until 1836.[2] He had been declared bankrupt in February of the previous year.[3]
He was at one time president of the Society of Engravers. His engravings were chiefly in stipple.[1] They include works after Richard and Maria Cosway, and a series of allegories of the months after Edward Francis Burney, published by Rudolf Ackermann in 1807–9.[2] His illustrations for Richard Payne Knight's Specimens of Ancient Sculpture, Aegyptian, Etruscan, Greek and Roman: Selected from different collections in Great Britain (1809), have been described by Nicholas Penny as "the finest ever made of sculpture".[2]