Douglas Johnstone (born 12 March 1969 in Irvine, North Ayrshire) is a Scottish footballer. He played professionally as a central defender before retiring and becoming a teacher at various schools around North Ayrshire, including the now demolished St Matthews Academy in Saltcoats. He teaches Mathematics up to an Advanced Higher level and is qualified to teach Computing.

He most famously played for Greenock Morton, before joining the later-to-become Morton players Kevin Finlayson, Allan Jenkins and failed trialist Derek Wingate at Stranraer.^[1]