Fibromyalgia (FM) is a prevalent problem that remains poorly understood and thus also difficult to treat. Mutually reinforcing relationships between pain and affect complicate mechanistic understanding and treatment development; high rates of comorbid affective disturbances compound pain-related suffering and make parsing the mechanistic underpinnings of FM particularly difficult. Over the last decade, spinal cord imaging has become a state-of-the-art technique to study chronic pain, and spinal cord alterations appear to play a critical role in FM. The goal of this proposal is to discern the effects of mindfulness on pain, affect and spinal cord activity among females with FM, with a hypothesis that mindfulness improves regulation of chronic pain with concordant neurobiological change. Participants will complete 4 weeks of digitally delivered Acceptance and Commitment Therapy, combined with in-person mindfulness training. Clinical questionnaires and spinal cord images before and after mindfulness training will then be evaluated for change over time. Treatments carefully tailored to target FM and its affective correlates and sequelae at their mechanistic roots in the spinal cord are critically needed, as current treatments for FM provide minimal pain relief, fail to produce parallel affective and lifestyle improvements, and come with a host of side effects.