This paper presents a series of tests on cold-formed high strength stainless steel square and rectangular hollow sections subjected to web crippling. The types of stainless steel investigated in this study were high strength austenitic and duplex material. The measured web slenderness value of the hollow sections ranged from 16.5 to 49.6.The testswere carried out under two loading conditions specified in theAmerican Specification and Australian/New Zealand Standard for cold-formed stainless steel structures, namely End-One-Flange and Interior-One-Flange loading conditions. The web crippling test strengths were compared with the design strengths obtained using the American, Australian/New Zealand and European specifications for stainless steel structures. In addition, the North American Specification for cold-formed carbon steel structural members was also used to predict the web crippling strengths and compared with the test results. Generally, it is shown that the design strengths predicted by the specifications are either unconservative or very conservative. Hence, a unified web crippling equation with new coefficients for cold-formed high strength stainless steel square and rectangular hollow sections is proposed in this paper. It is shown that the proposed web crippling equation is safe and reliable.