Gwilym Cuthbert Grindley (1903–1976) was a British psychologist, best known for pioneering work in what later became known as operant conditioning.

[2] Grindley's academic career began at the University of Bristol, where he studied physics; his first publications were on emission spectra,[3] based on work with A. M. Tyndall.

However, he became interested in animal learning, and began work under Conwy Lloyd Morgan, who was then emeritus Professor of Psychology and Ethics at Bristol.

He carried out pioneering research on learning in chickens,[4] working within the framework of Pavlovian conditioning.

Grindley subsequently moved to a faculty post at the Department of Experimental Psychology at the University of Cambridge, and in 1932 published his best known paper, on learning in guinea pigs.