Oral ulcerative and erosive lesions are commonly encountered in clinical practice and represent a diverse group of disorders with varied aetiologies, including recurrent aphthous ulcers, medication-induced stomatitis, Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis, tuberculosis, syphilis, traumatic ulcers, erosive lichen planus, Crohn’s disease, reactive arthritis, chronic ulcerative stomatitis, and radiation-induced mucositis. These lesions can significantly impact patients’ quality of life due to pain, impaired nutrition, and difficulty in speaking. Accurate diagnosis is often challenging and requires careful clinical evaluation supported by histopathological and laboratory investigations. This chapter provides an overview of the clinical presentation, differential diagnosis, and current approaches to management of ulcerative and erosive oral lesions.