Robert Edgeworth-Johnstone (4 February 1900 – 3 December 1994) was a British chemical engineer and inventor.
Born in Dublin, he spent 33 years in industry as a chemical engineer and consultant, working overseas in the oil industry.
A keen musician, Edgeworth-Johnstone developed the Johnstone flute, a simple version of the instrument made from the aluminium brass tubing used in oil refineries.
The instrument's design was admired by renowned flautist James Galway, but Edgeworth-Johnstone did little with the invention until he published details in a 1993 book.
He later became Lady Trent Professor of Chemical Engineering at the University of Nottingham and was involved in reforming the courses there to be more applicable to industry.
Edgeworth-Johnstone retired in 1967 but continued to work to advance engineering education, authoring a 1969 report on the subject for the Institution of Chemical Engineers.