This paper focuses on the web crippling performance of staggered slotted perforated Cold-Formed Steel (CFS) channels under Interior-One-Flange (IOF) load case, highlights the web crippling strength reduction, and provides reliable design guidelines. Finite Element (FE) analysis was employed to represent the IOF load case web crippling behaviour of staggered slotted perforated CFS channels. The developed FE models were then validated against laboratory tests on web crippling of CFS channels with both solid web and web openings under IOF load case. A parametric study (288 models) was conducted using the validated models to assess the effect of staggered slotted configurations and the corresponding degree of reduction in web crippling strength. It is shown that staggered slotted perforations play an important role in defining performance and may lead to a considerable reduction (up to 49%) in web crippling strength. Based on the results of the parametric study, new web crippling design equations were developed for IOF load case accounting the staggered slotted perforations. The web crippling strength predictions using the proposed equations yielded at a much higher level of accuracy, enhancing the commercial aspects of slotted perforated channels.