Dirk Willem "Dick" van Bekkum (30 July 1925 – 17 July 2015) was a Dutch medical-radiobiologist.
Van Bekkum was founder and head of the Radiobiological Institute of the Netherlands Organisation for Applied Scientific Research for thirty years.
At Leiden University he was professor of experimental transplantation biology and at the Erasmus University Rotterdam he was professor of radiobiology.
In the late 1960s he was one of the first to perform bone marrow transplants.