The Lorentz solution for Stokes flow in the presence of a plane wall is generalized to a surfactant-covered interface, and the Stokeslet solution is derived. The result is used to describe the motion of a small particle in the presence of the interface. The surfactant is insoluble and nondiffusing. The effects of surface viscosity are included. Small variations in surfactant concentration are assumed; this assumption usually holds under small capillary number conditions.