Sir Andrew Douglas Maclagan PRSE FRCPE FRCSE FCS FRSSA (17 April 1812, in Ayr – 5 April 1900, in Edinburgh) was a Scottish surgeon, toxicologist and scholar of medical jurisprudence.
He served as president of 5 learned societies: the Royal Medical Society (1832), the Royal College of Surgeons of Edinburgh (1859–61), the Royal College of Physicians of Edinburgh (1884–87), the Royal Society of Edinburgh (1890–5), and the Royal Scottish Society of Arts (1900).