Poor sleep quality is a common concern and a troublesome symptom among patients suffering from fibromyalgia. The purpose of this review was to identify and describe the available patient reported outcome measures (PROMs) of sleep quality validated in adult people diagnosed with fibromyalgia. The COSMIN and PRISMA recommendations were followed. An electronic systematized search in the electronic databases PubMed, Scopus, CINAHL Plus, PsycINFO, and ISI Web of Science was carried out. Validation studies of PROMs of sleep quality in fibromyalgia published in English or Spanish were included. The selection of the studies was developed through a peer review process through the online software "COVIDENCE". The quality of the studies was assessed using the COSMIN Risk of Bias checklist. A total of 5 PROMs were found validated in patients with fibromyalgia: (1) Pittsburgh Sleep Quality Index (PSQI), (2) Jenkins Sleep Scale (JSS), (3) Sleep Quality Numeric Rating Scale (SQ-NRS), (4) Medical Outcomes Study-Sleep Scale (MOS-SS), and (5) Fibromyalgia Sleep Diary (FSD). The quality of the evidence was very good and the quality of the results ranged from moderate to high. All the included PROMs, except for the FSD, showed adequate psychometric properties and, therefore, are valid and reliable tools for assessing sleep quality in the context of FM. However, none of the studies analyzed all the psychometric properties of the included PROMs as established in the COSMIN guidelines, highlighting that this is a potential field of research for future investigations. out in all experimental studies about FM. These results are in line with a previous internet survey, including 2596 people with FM [4], showing that poor sleep quality, together with pain, fatigue and morning stiffness, are the symptoms with greater severity and impact in these patients. Specifically, 79% of the participants perceived that sleep problems were one of the most common factors in the exacerbation of FM symptoms [4].In terms of prevalence, the studies indicate that between 65% and 99% of people diagnosed with FM report poor sleep quality [5][6][7]. Other authors [8] state that 63% of these patients report two or more symptoms of difficulty sleeping, while only 11.2% report having no problem sleeping. A recent meta-analysis of case-control studies indicated that, in comparison with healthy controls, people with FM show significantly lower sleep efficiency and sleep quality, shorter sleep duration, longer wake time after sleep onset and more percentage of light sleep stages when assessed with polysomnography. Subjective assessment showed that patients with FM have more difficulties falling asleep and worse sleep efficiency. Therefore, and although there are no conclusive data regarding the prevalence of poor sleep quality in FM, the results presented reveal that it is a recurrent and a concerning symptom among these patients [9]. Furthermore, poor sleep quality has been shown to be related with increases in the intensity of pain, and it is an aggravating factor o...