Numerical and physical modeling techniques are used to predict process behavior in friction stir welding (FSW) high strength aluminum alloys. The numerical approach uses a non-linear finite element method to characterize thermal and deformation behavior along the welded structure during FSW. Coupled temperature-displacement analysis is applied in order to determine temperature, displacement, and mechanical responses simultaneously. The physical modeling approach uses the response surface methodology (RSM) to evaluate the effects of the process controlling parameters on the properties of the welded joints. The results obtained, offer insights into the effects of the major process parameters in establishing successful FSW joints that satisfy further processing requirements and product service conditions.