Known for the development of a sum rule on two-photon processes, Roy is an elected fellow of all the three major Indian science academies – Indian Academy of Sciences, Indian National Science Academy and National Academy of Sciences, India – as well as of the American Physical Society. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded Roy the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards, for his contributions to physical sciences in 1987.