Fibromyalgia is a multifaceted syndrome primarily characterized by chronic widespread pain and fatigue. Despite its significant prevalence and incidence, the mechanisms mediating the disease pathogenesis have remained poorly understood; however, increasing evidence suggests a potentially central role of intestinal dysbiosis. Researchers have been examining possible diagnostic biomarkers, such as infection, urine metabolite profiles, and cytokine levels, which reflect these microbiome changes. Additionally, evaluation of therapeutic interventions targeting the gut microbiome, including probiotics, fecal microbiota transplantation, and antibiotics for specific infections, has highlighted their potential in alleviating fibromyalgia symptoms. This article delves into the emerging role of the gut microbiome in fibromyalgia pathogenesis, illustrating how alterations in gut bacterial composition and diversity are implicated in the pathophysiology of the disease through the gut-brain axis, and sets a direction for future research to enhance diagnostic accuracy and therapeutic efficacy of this complex condition.