Dispositional mindfulness (DM) has been linked to a number of mental health outcomes, including anxiety. Metacognitive models of anxiety posit that an individual's negative beliefs about the danger and uncontrollability of their worry predict the development and maintenance of anxiety disorders. The aim of the present study was to determine whether DM facets predict negative beliefs about worry, and subsequently (via indirect effects) anxiety. Participants (a nonclinical sample of university students; N = 446) volunteered to complete an online survey, which assessed DM, negative beliefs about worry, and anxiety. Multiple regression analyses confirmed that Nonjudgment, Nonreactivity, and Act Aware facets of DM significantly predicted negative beliefs about worry, with negative associations. Furthermore, negative beliefs about worry significantly mediated the relationship between these facets of DM and anxiety symptoms. The Observe facet, however, was not a significant predictor of negative beliefs about worry, nor were any significant indirect effects found with anxiety. The current investigation is the first to investigate the relationship between facets of DM and negative beliefs about worry. Clarification of the roles of DM and negative beliefs about worry in anxiety extends our understanding of metacognitive models of psychopathology, and informs preventative approaches to mental health.