Cold-formed stainless steel beams are often subjected to concentrated, localised loads or reactions. These concentrated forces acting on flexural members cause localised bearing failures. This bearing failure, generally known as web crippling, is one of the critical failure modes of cold-formed stainless steel members. The provision of web opening at an appropriate location in such section is also important to avoid holes being cut at an inappropriate location during the construction stage. Different shapes and sizes of web openings are made on the web panel of such sections to facilitate building services. The scope of this study is however limited to stainless steel Lipped Channel Beams (LCB) with square and rectangular web openings. Presence of opening in the web directly influences the web crippling behaviour and also considerably reduces web crippling strength of stainless steel LCBs, but very limited researches have been undertaken to predict the web crippling capacity of stainless steel LCBs. Hence, a detailed finite element analysis was undertaken to investigate the web crippling behaviour and web crippling strength of cold-formed stainless steel LCBs with centered non-circular web opening under the exterior-two-flange (ETF) loading condition. Finite element models of cold-formed stainless steel beams with web opening under web crippling actions were developed to investigate the ultimate web crippling strength behaviour of cold-formed stainless steel beams with web opening including their elastic and post-buckling characteristics. They were validated with currently available web crippling test results. A detailed parametric study based on validated finite element model was undertaken to develop an extensive web crippling strength database and were then used to develop the new design equations for the reduction factor of web crippling capacities of cold-formed stainless steel beams with non-circular (i.e. Square or rectangle) web opening. Appropriate web crippling design rules within the framework of European and International Standards were developed based on obtained FEA results.