The Beliefs about Losing Control Inventory (BALCI) was developed to assess negative beliefs about losing control in obsessive-compulsive disorder (OCD). Since its creation, research and theoretical work support negative beliefs about losing control as a potential transdiagnostic construct. The present study revised and expanded the original BALCI to be more inclusive of control-related concerns beyond those that would be expected in OCD (e.g. concerns about losing control over how one comes across to others in social anxiety disorder; SAD). Undergraduate students (N = 440) completed a questionnaire battery including the BALCI-II item pool. An exploratory factor analysis of the 32-item BALCI-II supported a four-factor solution. Three of the identified factors capture the feared consequences of losing control: 1) overwhelming emotions, 2) dangerous behaviour, and 3) madness. The fourth factor captures inflated beliefs about probability/severity of those losses. The BALCI-II was found to have good convergent and divergent validity, good to excellent internal, and retest reliability and was shown to have predictive utility in both OCD and SAD, above and beyond existing disorder-specific maladaptive belief domains. Results suggest the BALCI-II is an improvement over the previous version and supports the relevance of these beliefs beyond OCD.