John Seymour Lucas (21 December 1849 – 8 May 1923) was a Victorian English historical and portrait painter, as well as an accomplished theatrical costume designer. He was born into an artistic London family (he was the nephew of the painter John Lucas), and originally trained as a woodcarver, but turned his attention to portrait painting and entered first the St. Martin's Lane Art School and later the Royal Academy Schools. Here he met fellow artist Marie Cornelissen from France, whom he married in 1877. Lucas' artistic education included extensive travels around Europe, particularly Holland and Spain, where he studied the Flemish and Spanish masters. He first started exhibiting in 1872, was elected an associate member of the Royal Academy in 1886, and a full Royal Academician in 1899.