John Farley Leith, QC (5 May 1808 – 4 April 1887)[1] was a British lawyer and Liberal politician.

He was the eldest son of James Urquhart Murray Leith, of Barrach, Aberdeenshire, killed in 1814 at the Battle of Orthez with the 68th Regiment.

[2][3] Leith practised as a barrister in the Calcutta High Court from 1832 to 1846 and was then Professor of Law at the East India Company's Haileybury College from 1853 to 1857.

[2] In 1832 Leith married Alicia Anne, the daughter of Samuel Tomkins (the elder) of London, a banker, with whom he had issue.

[2][3] Their daughter Mary Anne married Sir William Miller, 1st Baronet.