John Sinclair, Lord Murkle (died 5 June 1755) was a Scottish judge.
A son of John Sinclair, 8th Earl of Caithness and Janet Carmichael of the Hyndford family, he was admitted to the Faculty of Advocates on 7 February 1713.
He was elevated to the bench on the death of Sir William Calderwood of Polton on 3 November 1733, with the judicial title Lord Murkle.
An Historical Account of the Senators of the College of Justice from its Institution in MDXXXII by George Brunton and David Haig, published by Thomas Clark MDCCCXXXII
This Scottish law-related biographical article is a stub.