Catastrophic thinking is associated with disability and distress for many with chronic pain. The effects of catastrophic thinking likely rely not only on the content or frequency of the thoughts, but also on other cognitive, behavioral, and environmental influences that are present. One possible influence is acceptance, which involves experiencing thoughts, moods, or sensations without some of their supplemental psychological effects on behavior, especially when these effects can contribute to less freedom in living. The present study sought to explore how acceptance influences the relations between catastrophizing and patient functioning in 344 individuals with chronic pain. Analyses indicated that acceptance mediated the effects of catastrophic thinking on depression, anxiety and avoidance, and physical and psychosocial functioning with indirect effect tests suggesting that the variance in functioning predicted by catastrophizing was significantly reduced with the inclusion of acceptance. These results suggest that research and clinical work in the area may benefit from a broadened perspective where the occurrence of catastrophic thinking is considered within the wider context of the behavioral processes that give this thinking its impact.