John Syme (1795–1861) was a Scottish portrait-painter.
A nephew of Patrick Syme, he was born in Edinburgh and studied in the Trustees' Academy. He became a pupil and assistant of Sir Henry Raeburn, whose unfinished works he completed, and subsequently practised with success as a portrait-painter in Edinburgh.
Syme was an original member of the Royal Scottish Academy, founded in 1826, and took an active part in its management. He died in Edinburgh on 3 August 1861.
He painted many portraits. That of John Barclay M.D. was exhibited at the London Royal Academy in 1819, and went to the Scottish National Gallery; it was engraved in mezzotint by Thomas Hodgetts, as were also those of John Broster and Andrew McKean. Syme's self-portrait went to the Royal Scottish Academy.