Fibromyalgia (FM) is a medical condition defined by the presence of chronic widespread pain, fatigue, waking unrefreshed, cognitive symptoms, lower abdominal pain or cramps, and depression. Other symptoms include insomnia and a general hypersensitivity.

The cause of fibromyalgia is unknown, but is believed to involve a combination of genetic and environmental factors. Environmental factors may include psychological stress, trauma, and certain infections. The pain appears to result from processes in the central nervous system and the condition is referred to as a "central sensitization syndrome".

The treatment of fibromyalgia is symptomatic and multidisciplinary. The European Alliance of Associations for Rheumatology strongly recommends aerobic and strengthening exercise. Weak recommendations are given to mindfulness, psychotherapy, acupuncture, hydrotherapy, and meditative exercise such as qigong, yoga, and tai chi. The use of medication in the treatment of fibromyalgia is debated, although antidepressants can improve quality of life. The medications duloxetine, milnacipran, or pregabalin have been approved by the US Food and Drug Administration (FDA) for the management of fibromyalgia. Other common helpful medications include serotonin-noradrenaline reuptake inhibitors (SNRI), non-steroidal anti-inflammatory drugs (NSAIDs), and muscle relaxants. Q10 coenzyme and vitamin D supplements may reduce pain and improve quality of life. While fibromyalgia is persistent in nearly all patients, it does not result in death or tissue damage.

Fibromyalgia is estimated to affect 2–4% of the population. Women are affected about twice as often as men. Rates appear similar in different areas of the world and among different cultures. Fibromyalgia was first defined in 1990, with updated criteria in 2011, 2016, and 2019. The term "fibromyalgia" is from New Latin fibro-, meaning "fibrous tissues", Greek μυο- myo-, "muscle", and Greek άλγος algos, "pain"; thus, the term literally means "muscle and fibrous connective tissue pain".