Experimental investigation of Concrete-filled lean Duplex Stainless Steel (LDSS) Rectangular Hollow Section (RHS) stub columns has been presented. A total of 13 stub columns, 10 concrete-filled and 3 without concrete infill, under axial compression was conducted. The RHS had overall depth-to-width ratio varied from 1.3 to 2.0, and overall depth-to-thickness ratio varied from 26 to 40. The nominal cylinder strengths of concrete ranged from 30 to 110 MPa. In this study, the effect of concrete strength was investigated. The stub column strengths were compared with the design strengths predicted using the American, Australian, and European specifications. It is found that the design strengths predicted by the aforementioned specifications are generally conservative. The design strengths predicted by the American Specification are found to be generally slightly more conservative than the Australian and European specifications.