In this paper, effect of thickness on the structural performance of concentrically loaded semi-elliptical lean duplex stainless steel (LDSS) hollow stub columns is presented via nonlinear finite element (FE) analysis by using ABAQUS. The modeling procedure has been validated against the LDSS stub column experimental results available in literature. The cross-sectional dimensions considered in this analysis conform to the commercially available semi-elliptical hollow sections from Ancofer Stahlhandel GMBH. Extensive parametric study was carried out to study the structural performance by varying the thickness from t = 5 to 14 mm. Based on the FE analyses, it has been found that, for the sections considered, a near linear increase (~+300%) in column resistance (Pu) is seen with increase (~+180%) in thickness from t = 5 to 14 mm. Further, an enhanced strain hardening effect on the load capacity can be observed for the thicker sections, i.e., t ≥ ~12.5 mm. © 2019, Springer Nature Singapore Pte Ltd.