Resistance spot welding (RSW) is widely employed in sheet metal fabrication, in particular in automotive bodies and structures. Manufacturers are increasingly demanding reduced design periods with improved safety requirements, which could potentially be achieved through computational simulations. This paper presents an integrated approach combining simulation of the welding process, materials characterisation and mechanical modelling to study the effect of welding parameters on the strength of spot-welded joints. The welding process was simulated and the dimensional attributes were used to build the mechanical models for strength analysis. The constitutive material properties of the base, nugget and the heat-affected-zone (HAZ) were determined by an inverse FE modelling approach using indentation test data. The predicted deformation of spot-welded joints of a typical automotive steel under tensile-shear load showed a good agreement with experimental results. The validated models were further used to predict effects of welding parameters on the strength and failure behaviour of weld joints. Potential uses of the approach in optimising welding parameters for strength were also discussed.