Local halitosis affects a substantial proportion of adults and is predominantly of intraoral origin. Volatile sulfur compounds, principally hydrogen sulfide and methyl mercaptan, are generated by anaerobic bacteria acting on sulfur-containing amino acids within periodontal pockets and tongue biofilms. Periodontal disease, tongue coating, reduced salivary flow, carious lesions, and prosthetic factors are the main local contributors. This review provides dental clinicians with a concise, evidence-based overview of the etiological factors and their underlying mechanisms.