For decades, Lebanon was war-torn by civil strife, and occupation and invasion by neighboring countries. In time, these wars have escalated in intensity from sniping, barricading streets and random shelling of residential quarters to the use of rockets, aerial bombing, and heavy artillery. Adverse mental health effects are noted in times of war with post traumatic stress disorder (PTSD) as a main outcome. The aim of this study was to carry out a systematic review of published studies documenting the prevalence of PTSD in the adolescent population of Lebanon, to investigate the increase in these rates with the escalation of war intensity, and to examine PTSD determinants. A search strategy was developed for online databases (PubMed and Google Scholar) between inception to the first week of January 2013. Search terms used were PTSD, adolescents and Lebanon. Eleven studies reporting PTSD in adolescents met the inclusion criteria for a total number of 5965 adolescents. Prevalence rates of PTSD ranged from 8.5% to 14.7% for the civil war, 3.7% for adolescents with sensory disabilities, 21.6% for the Grapes of Wrath War, and 15.4% to 35.0% for the 2006 July War. Some increase in PTSD rates in time is noted. Type of trauma such as bereavement, injury, house destruction, and economic problems, low self efficacy and scholastic impairment were related to PTSD. These findings may help in the development of public health policies for PTSD prevention and treatment for the protection of adolescents from war atrocities and their consequences.