Isaac Fuller (1606(?) – 1672) was an English painter. Trained in France, he worked in Oxford and London. His works included portraits, religious subjects and decorative paintings.
Fuller is often said to have been born in 1606, but may have been born as late as 1620. According to Bainbrigge Buckeridge, writing at the beginning of the 18th century, he studied under the French Baroque painter François Perrier in Paris.
During the earlier part of the 1660s Fuller decorated the chapels of Magdalen and All Souls Colleges at Oxford. His work at Magdalen, representing the Resurrection is lost, but a print survives, showing a complex and ambitious composition, derived ultimately from Michelangelo. At All Souls he painted a fresco of The Last Judgement, which is also lost, although some additional panels by Fuller, originally fitted between the roof-trusses in the chancel, survive. John Evelyn said that the fresco would not last long, being "too full of nakeds". He also painted an altarpiece for the chapel at Wadham College, using an unusual technique in which the image was drawn on grey cloth in brown and white crayons, and then ironed into the fabric.Joseph Addison wrote a poem in praise of it.
In London Fuller did a lot of work as decorative painter, especially in taverns. These included the Sun near the Royal Exchange, and the Mitre in Fenchurch Street, where he decorated the walls of a large room with life-sized mythological figures, and the ceiling with two angels holding a mitre. He also painted the ceiling over the staircase in a house in Soho Square, and a ceiling at Painter-Stainers' Hall.
While at Oxford he painted portraits, and also copied William Dobson's Decollation of St. John, altering the heads to portraits of his own friends. As a portrait painter Fuller had some real power, and self-portrait, in the Bodleian Library at Oxford, shows him in a curious head-dress. John Elsum wrote an epigram on it. There is a related drawing by Fuller in the collection of the Victoria and Albert Museum, probably the preparatory work for a print. There is a portrait of Fuller, drawn by George Vertue, in the collection of the British Museum.