Background <p>Endo-Periodontal Lesions (EPLs) are complex conditions that significantly affect tooth prognosis and require accurate diagnosis and coordinated endodontic–periodontal management. However, evidence regarding diagnostic awareness and knowledge related to EPLs among dental students and dentists remains limited. This study aimed to evaluate diagnostic awareness, disease-related knowledge, educational perceptions, and self-reported clinical practices regarding EPLs across different educational and professional levels.</p> Methods <p>This cross-sectional study included 584 dental students and dentists who completed a 20-item online questionnaire regarding EPL-related awareness, knowledge, educational perceptions, and clinical practices. Comparisons were performed across educational and professional groups.</p> Results <p>Awareness, perceived knowledge, and self-reported clinical practices regarding EPLs varied across educational and professional levels. Clinical-stage students reported greater familiarity with EPL-related concepts and higher diagnostic confidence than preclinical students. Specialist dentists demonstrated greater clinical involvement with EPLs and greater familiarity with contemporary classification systems than general dentists. Clinical training stage remained independently associated with self-reported ability to identify EPLs.</p> Conclusions <p>Self-reported awareness, perceived knowledge, and reported clinical practices regarding EPLs differ according to educational and professional experience. Clinical training appears to play an important role in improving diagnostic familiarity and confidence. These findings highlight the importance of structured and integrated educational approaches to improve the recognition and management of EPLs in both undergraduate and postgraduate dental training.</p>