A three-dimensional finite element model of the glenoid was used to examine stresses in glenoids with and without total shoulder arthroplasty components. The glenoid components were metal-backed with a polyethylene liner. Two Young’s Moduli and four thicknesses were used for the metal backings in order to study the effect of metal backing flexibility on stress shielding. The metal backings were modelled with and without pegs. The effect of a complete or partial removal of the subchondral bone thickness was studied. A central and a superior joint contact force were modelled. Stress shielding due to glenoid components was examined by comparing bone stresses in the implanted glenoid with bone stresses in the natural glenoid. The use of thinner metal backings reduced stress shielding although the thinner backings caused higher tensile stresses in the backing itself, particularly with the high Young’s Modulus material. The use of a metal backing material with a lower Young’s Modulus reduced stress shielding, although a large Modulus reduction was required to produce a substantial effect. A sensitivity analysis of the values used for the cortical and cancellous bone Young’s Moduli showed little effect on the stresses in the implanted glenoids when normalised against the stresses in the natural glenoid. The addition of pegs to the metal backing increased stress shielding in the bone surrounding the pegs. The superior load case caused the components to tip superiorly which caused peak compressive stresses by pressing the superior edge of the metal backing into the underlying bone. Tipping of the implant caused the pegs to bend superiorly which created large stresses in the bone around the peg holes. The inclusion of a fibrous tissue layer between the metal backing and the subchondral bone exacerbated this situation. An experimental determination of the trabecular structure in cadaver glenoids showed a qualitative agreement between the orientation of the trabeculae and the principal stress directions calculated in the finite element analysis.