Fibromyalgia (FM) is a common chronic pain disorder that presents diagnostic challenges for clinicians. Several classification, diagnostic and screening criteria have been developed over the years, but there continues to be a need to develop criteria that reflect the current understanding of FM and are practical for use by clinicians and researchers. The Analgesic, Anesthetic, and Addiction Clinical Trial Translations Innovations Opportunities and Networks (ACTTION) public-private partnership with the U.S. Food and Drug Administration (FDA) and the American Pain Society (APS) initiated the ACTTION-APS Pain Taxonomy (AAPT) to develop a diagnostic system that would be clinically useful and consistent across chronic pain disorders. The AAPT established an international FM working group consisting of clinicians and researchers with expertise in FM to generate core diagnostic criteria for FM and apply the multidimensional diagnostic framework adopted by AAPT to FM. The process for developing the AAPT criteria and dimensions included literature reviews and synthesis, consensus discussions, and analyses of data from large population-based studies conducted in the United Kingdom. The FM working group established a revised diagnosis of FM and identified risk factors, course, prognosis, and pathophysiology of FM. Future studies will assess the criteria for feasibility, reliability, and validity. Revisions of the dimensions will also be required as research advances our understanding of FM. PERSPECTIVE: The ACTTION-APS FM taxonomy provides an evidence-based diagnostic system for FM. The taxonomy includes diagnostic criteria, common features, comorbidities, consequences, and putative mechanisms. This approach might improve the recognition of FM in clinical practice.