Bimal Kumar Roy (Bengali: বিমল কুমার রায়) is an Ex-Director of the Indian Statistical Institute. He is a renowned cryptologist from the Cryptology Research Group of the Applied Statistics Unit of ISI, Kolkata. He received a Ph.D. in Combinatorics and Optimization in 1982 from the University of Waterloo under the joint supervision of Ronald C. Mullin and Paul Jacob Schellenberg.
In June 2015 Prof. Roy was removed from his post of director of ISI, just one month before the end of his appointment. This action was harshly criticised by the international academic community.
Currently he is working on Combinatorics, and application of Statistics in Cryptology and Design of Experiments. In 2015, Prof Roy was awarded Padma Shri, India's fourth highest civilian honour, recognizing his accomplishments and contribution to education.