Objective <p>While the link between cyberbullying victimization and perpetration and depressive symptoms in adolescents is well-established, their lasting effects and potential mechanism require further investigation.</p> Methods <p>A total of 1,401 adolescents (<i>M</i>_<i>age</i> = 15.497, <i>SD</i> = 0.568) from China participated in the study. Cyberbullying victimization, perpetration, core self-evaluation, and depressive symptoms were assessed at baseline (Wave 1, W1), one year later (Wave 2, W2), and two years later (Wave 3, W3).</p> Results <p>Cyberbullying victimization at W1 positively predicted depressive symptoms at W2 but not at W3, whereas cyberbullying perpetration did not predict depressive symptoms at W2 but emerged as a negative predictor at W3. Mediation analysis further revealed that cyberbullying victimization at W1 reduced core self-evaluation at W2, which in turn heightened depressive symptoms at W3. Conversely, cyberbullying perpetration at W1 improved core self-evaluation at W2, subsequently alleviating depressive symptoms at W3.</p> Conclusion <p>These findings highlighted the distinct long-term effects of cyberbullying victimization and perpetration on depressive symptoms. Collectively, the results indicated that enhancing core self-evaluations, such as through targeted self-reflection programs or resilience-building exercises, could serve as an effective protective strategy to reduce the negative impact of cyberbullying victimization on depressive symptoms.</p>