Anxiety and related disorders are a significant public-health burden with rising prevalence in the wake of the COVID-19 pandemic. As demand for effective anxiety treatment increases, so too does the need for strategies to bolster treatment outcomes. Research on the mechanisms of exposure therapy, the frontline behavioral treatment, will be critically important for optimizing clinical outcomes. We outline an initial agenda for future research on the mechanisms of change of exposure therapy, developed in collaboration with a large international team of researchers through the Exposure Therapy Consortium. Key questions and recommendations for future research focus on four priority areas: conceptualization, measurement, study design/analysis, and individual/contextual differences. Rising to the challenge of addressing these questions will require coordinated action and availability of centralized tools that can be used across trials, settings, and research groups.