Although shear walls are a widely used system for providing lateral load resistance, nonlinear analysis procedures for this type of element are much less well developed than those for frame and truss elements. Equivalent flexural models do not include shear deformation and are only suited for symmetric, straight walls. This paper describes the development of an analysis model which includes nonlinear effects for both shear and flexure. The formulation is based on a "macro" modelling approach which is suitable for complete building models in a design office environment. An analysis methodology is developed using engineering mechanics and experimental results and implemented in an existing nonlinear analysis computer program. A model is developed and validated against test results of solid walls and walls with openings. This shows that the model can capture the general characteristics of hysteretic response and the maximum strength of the wall. Results can be evaluated using acceptance criteria derived from published guidelines. An example shear wall building is then evaluated using both the nonlinear static and the nonlinear dynamic procedures. The procedure is shown to be a practical method for implementing performance based design procedures for shear wall buildings.