We have measured the diamagnetic shift of band‐edge luminescence, no‐phonon peak, and phonon sideband from a pseudomorphic, undoped Si0.83Ge0.17/Si quantum well using high‐field magnetoluminescence spectroscopy. The quadratic dependence of the diamagnetic shift of the no‐phonon luminescence peak suggests that the luminescence originates from excitons. Using a variational calculation, we determine the effective heavy‐hole mass and the exciton binding energy to be 0.27m0and 14.8 meV, respectively, and compare these results with reported values obtained from other measurement techniques. ©1995 American Institute of Physics.