Valentine Cameron "Val" Prinsep RA was a British painter of the Pre-Raphaelite school.

Born in Calcutta, India, he was the second child of Henry Thoby Prinsep, a civil servant of the British Raj, and his wife Sarah Monckton Pattle, daughter of James Pattle. His mother was a sister of the photographer Julia Margaret Cameron and Maria Jackson (née Pattle), grandmother of Virginia Woolf and Vanessa Bell.

Henry and Sarah Prinsep returned to England in 1843. They settled in 1851 at Little Holland House, and made it a centre of artistic society.

Henry Thoby Prinsep was a friend of the painter George Frederic Watts, under whom his son first studied, and travelled with Watts in 1856–57 to Sir Charles Thomas Newton's excavation of Halicarnassus. He then went to Charles Gleyre's atelier in Paris. There James Abbott McNeill Whistler, Edward Poynter, and George du Maurier were among his fellow students, and he was later the original for Taffy in Du Maurier's novel Trilby. After Paris, Prinsep passed to Italy. With Edward Burne-Jones he visited Siena and there made the acquaintance of Robert Browning, of whom he saw much in Rome during the winter of 1859–60.

Prinsep was a close friend of John Everett Millais, and of Burne-Jones, with whom he travelled further in Italy. He had a share with Dante Gabriel Rossetti and others in the decoration of the hall of the Oxford Union. With other members of the Pre-Raphaelite Brotherhood, he taught at the Working Men's College during the mid-19th century. He first exhibited at the Royal Academy of Arts in 1862 with his Bianca Capella, his first picture, which attracted notice as a portrait (1866) of General Gordon in Chinese costume. Prinsep lent the costume to Millais who used it in his own painting Esther.

From 1862 to his death Prinsep was an annual exhibitor at the Royal Academy. He was elected A.R.A. in 1879 and R.A. in 1894. His marriage in 1884 made Prinsep a wealthy man, and he became a company director and landowner.

Prinsep died at Holland Park, west London in 1904, and is buried in Brompton Cemetery, London. He was buried with his wife Florence. The distinctive Roman style monument lies on the western path between the north entrance and the central buildings. He was an enthusiastic volunteer, and one of the founders of the Artists Rifles.