Oral mucositis (OM) is a common adverse effect in cancer patients who undergo oncology treatment. It affects the oral mucosa through erythema areas to extensive ulcerations. OM is classified in grades based on its clinical presentation and symptoms. The consequences of OM include an increased risk of infections, a decrease in food intake that leads to loss of weight, dehydration, a higher opioid use, loss of status performance, and consequently increasing medical costs and treatment interruption, which negatively impacts the prognosis and tumor control. Several treatments are available for OM management, such as anti-inflammatory drugs, analgesics, mouthwashes, and topical agents. However, photobiomodulation therapy has been suggested as the most effective option to prevent and treat OM. Recent studies using this therapy have demonstrated promising results leading to decreased inflammation, pain control, healing, and decreased severity of OM in the prophylactic and therapeutic settings.