The effects of viscosity on a steady, radial, spherically symmetric solar wind with an embedded, non-radial magnetic field are reconsidered. The correct expression for the classical viscosity in the presence of a non-radial magnetic field is shown to be different from that used in the past, and a means of describing non-classical viscosity is presented. A physical interpretation of the classical and nonclassical description of viscosity is provided, and observational inferences are used in discussing the nature and degree of viscous effects in the solar wind.