Kalyan Bidhan Sinha (K.B. Sinha) (born 3 June 1944) is an Indian mathematician. He is a professor at the Jawaharlal Nehru Centre for Advanced Scientific Research, and Professor Emeritus for life of the Indian Statistical Institute. Sinha is the author of numerous scientific works in scattering theory, spectral theory of Schrödinger operators, quantum stochastic calculus, noncommutative geometry, and, more broadly, in mathematical physics.