Background: Safety behaviours are ubiquitous across anxiety disorders and are associated with the aetiology, maintenance and exacerbation of anxiety. Cognitive behavioural models posit that beliefs about safety behaviours directly influence their use. Therefore, beliefs about safety behaviours may be an important component in decreasing safety behaviour use. Unfortunately, little empirical research has evaluated this theorized relationship. Aims: The present study aimed to examine the predictive relationship between beliefs about safety behaviours and safety behaviour use while controlling for anxiety severity. Method: Adults with clinically elevated levels of social anxiety (n = 145) and anxiety sensitivity (n = 109) completed an online survey that included established measures of safety behaviour use, quality of life, and anxiety severity. Participants also completed the Safety Behaviour Scale (SBS), a measure created for the current study which includes a transdiagnostic checklist of safety behaviours, as well as questions related to safety behaviour use and beliefs about safety behaviours. Results: Within both the social anxiety and anxiety sensitivity groups, positive beliefs about safety behaviours predicted greater safety behaviour use, even when controlling for anxiety severity. Certain beliefs were particularly relevant in predicting safety behaviour use within each of the clinical analogue groups. Conclusions: Findings suggest that efforts to decrease safety behaviour use during anxiety treatment may benefit from identifying and modifying positive beliefs about safety behaviours.