Roy is one among the Indian participants in the Oxford-India Network in Theoretical Physical Sciences, an initiative promoted by the John Fell Fund. He was a member of the research committee of the Council of Scientific and Industrial Research during 1991–94. Roy served as the chairman of the Physics Graduate School from 1992 to 1997 and the Department of Theoretical Physics from 1997 to 2002, both based at Tata Institute of Fundamental Research. He sat in the governing council of S.N. Bose National Centre for Basic Sciences from 1997 to 2002 and in the editorial boards of Indian Journal of Pure and Applied Physics, Pramana and Indian Journal of Physics during various terms. He also served as the vice-president of the Indian Physical Society in 1996 and presided the society in 2002.