Simulations of the 1991 Mt. Pinatubo eruption are used to study how radiative heating by volcanic aerosols alters stratospheric winds. We found that heating of the tropical stratosphere by volcanic aerosols drives increased wind speeds in the midlatitude vortex region. A theoretical framework is then used to identify the dynamical origin of these enhanced winds, which we find to be a combination of a strengthened global circulation and a modification of large-scale atmospheric waves.