Background: For a long time, Lebanon has been considered an unstable country. This can have a negative impact on Lebanese adolescents that consequently face secondary emotional stress, leading to more mental health problems such as anxiety, depression, and alexithymia. The objective of this study was to assess the association between alexithymia, depression and aggressive behavior in a sample of Lebanese adolescents. Methods: This is a cross-sectional study, conducted between September 2018 and February 2019, which enrolled 568 young adolescents aged between 15 and 18 years using a proportionate sample from two Lebanese governorates. Out of 750 questionnaires distributed, 568 (75.73%) were completed and collected back. Results: The mean age was 15.87 ± 0.82 years, with 302 (53.2%) females; 180 (31.7%) were alexithymic, 193 (34.0%) and 181 (31.9%) had moderate (scores between (89 and 111) and high (scores ≥ 112) aggression respectively, whereas 176 (31.0%) and 149 (26.2%) had moderate (scores between 3 and 4) and high (scores ≥ 5) depression respectively. Higher levels of alexithymia were significantly associated with higher depression (Beta = 0.44), higher total aggression (Beta = 0.78), higher physical aggression (Beta = 0.24), higher verbal aggression (Beta = 0.14), higher anger (Beta = 0.22), and higher hostility (Beta = 0.19). Conclusion: The prevalence of alexithymic behaviors, as well as aggression and depression in Lebanese students appears to be very high in comparison with students worldwide. Alexithymia was significantly associated with higher depression, physical and verbal aggression, anger and hostility among adolescents. Factors underlying the high level of alexithymia remain not fully elucidated.