Previous research has implicated reductions in anxiety sensitivity (AS) – the dispositional tendency to fear anxiety-related sensations – as critical to change during cognitive behavioral therapy (CBT) for anxiety. However, the relationship of AS to anxiety symptom remittance following CBT remains largely unknown. To address this gap, the current study evaluated prospective associations between AS and symptoms of various anxiety disorders following completion of the Coordinated Anxiety Learning and Management (CALM) study– a large clinical trial evaluating the efficacy of a brief, computer-facilitated CBT intervention for transdiagnostic anxiety within primary care. Participants were randomized to CALM (n = 460) or a control treatment (n = 501) and completed self-report measures of general and disorder-specific anxiety symptoms at pretreatment and at 6-month, 12-month, and 18-month follow-up. Longitudinal relations between AS and each anxiety measure across timepoints and within each treatment group were assessed using cross-lagged panel models. Results indicated that higher AS following CALM predicted greater anxiety symptoms at the subsequent timepoint for all anxiety symptoms except social anxiety symptoms. Higher anxiety following treatment also predicted later AS. These findings implicate AS as an indicator of transdiagnostic anxiety remittance and suggest that targeting AS could be useful for reducing clinical anxiety relapse following CBT.