A model of elastohydrodynamic lubrication of reciprocating engine piston skirts was developed in the context of a simulation of piston secondary motions. The piston secondary dynamics, skirt lubrication and skirt elastic deformation problems are simultaneously solved in the calculation. The model can represent both conventional and two-piece articulated pistons and also includes a treatment of wrist pin lubrication. Skirt deformations are calculated using a skirt compliance matrix derived from a finite element model of the piston. The model exercised to calculate piston secondary motions and skirt deformations for a heavy-duty truck diesel piston at various operating conditions. Results show that peak skirt radial deformations can exceed the skirt-liner radial clearance and depend strongly on load. Articulated piston skirt deformations were shown to be significantly larger than those in conventional piston skirts.