James Weir McLachlan (16 August 1862 – 18 September 1938) was an Australian politician.
He was born in Harcourt to saddler William Ramsay McLachlan and Mary Weir.
He attended state schools and was a pupil teacher before inheriting the family's Sale saddlery.
In 1908 he was elected to the Victorian Legislative Assembly as the Labor member for Gippsland North.
He married Celia Sarah Hearn on 23 December 1912; they had two children.