John Sligo of Carmyle FRSE (1794–1858) was a 19th-century Scottish merchant and amateur geologist.
He was born in 1794 in Leith the son of John Sligo of Carmyle (d.1808) and his wife Christian Knox. His father was a tea and spirit merchant trading on Broad Wynd just off the Shore.
In 1820 his widowed mother was living at 9 Constitution Street in Leith.
John lived at 5 Drummond Place in Edinburgh's Second New Town from the 1820s.
In 1827 he became a member of the Highland Society. In 1832 he was elected a Fellow of the Royal Society of Edinburgh his proposer being Thomas Allan.
In 1857 he is listed as a Director of the Edinburgh to Bathgate Railway (part of the North British Railway).
He died at 5 Drummond Place in 1858 aged 63.