The protoplanetary nebular analog to the planetary Rossby wave is developed. Linear dispersion relations are derived. It is found that the nebular Rossby wave propagates freely in the nebular azimuthal direction and slowly grows in the radial direction. Possible ramifications for the nebula are raised for the reverse transition of turbulence into Rossby waves and zonal jets via the Rhines mechanism (P. B. Rhines 1975, J. Fluid Mech.69, 417-443), specifically, the formation of long-lived vortices and the accretion of solid bodies.