We report evidence for superrotation of plasma in the pre-dawn magnetosphere of Jupiter during the outbound segments of the Voyager 1 and 2 encounters. The evidence consists of a forward spiral of magnetic field lines crossing the equatorial plasma sheet, as distinct from the more typical backward spiral associated with subcorotational flow. (The Voyager plasma instruments were not pointed favorably for measurement of the azimuthal flow component during the outbound trajectories.) The limited available statistics indicate that superrotational flow is restricted in local time to the night side, and also restricted in system III longitude to the hemisphere opposite the active sector of the magnetic-anomaly model. The results are thus compatible with the planetary-wind concept in general and with the corotating convection model in particular.