� 2019 Canadian Society for Civil Engineering. All rights reserved. This paper presents a numerical study on the compressive behaviour of concrete-filled steel square columns subjected to concentric and eccentric loading conditions. Numerical models are developed using general purpose finite element (FE) software ABAQUS and have been validated using the available test results in the literature. The FE models predict the experimental load-deformation curve, ultimate strength and failure modes with good accuracy. Furthermore, the experimentally validated FE models are used to carry out a series of parametric study to investigate the effect of geometric and material properties on the behaviour of concentrically and eccentrically loaded concrete-filled steel square columns. Concrete compressive strength, steel yield strength, column depth to thickness ratio, and load eccentricity ratio are the key parameters that are varied in the FE models to assess their effect on the ultimate behaviour of concrete-filled steel columns. Finally, numerical results are compared with the existing AISC design guideline which clearly shows conservative nature of code predictions.