Rob Grootendorst (11 February 1944 in Schiedam – 23 February 2000 in Amsterdam) was a Dutch communication and argumentation theory scholar. He was professor for Dutch speech communication at the University of Amsterdam. His contributions to the argumentation field include the co-foundation of the pragma-dialectic school in argumentation theory.
He also wrote several books on the life and works of the Dutch writer and politician Theo Thijssen.