Lachlan MacLachlan (9 May 1791 – 30 April 1849)^[1] was Scottish-born barrister and, briefly, a Repeal Association MP.

MacLachlan, the son of Robert MacLachlan and Mary Campbell, was born in Strathlachlan.^{[citation needed]}

MacLachlan became Repeal Association Member of Parliament (MP) for Galway Borough in 1832 but was unseated on petition on 30 April 1833.^[2]

He was awarded the compensation for the enslaved people on Pembroke estate in Tobago, as he was, alongside Andrew Henry Lynch and James Campbell, an assignee of a mortgage, probably as executors and beneficiaries of the will of his uncle Lt General James Campbell (1743–1820).^[3]

MacLachlan died in Galway in 1849.^{[citation needed]}