Sex trafficking contributes to the cycle of violence against women, and inflicts global social and health consequences, particularly in this era of HIV/AIDS pandemic. This paper is based on a cross-sectionalsurvey conducted in two urban and two rural schools located in Delta and Edo states of Nigeria. The aim is to assess in-school students’ knowledge and awareness of, and attitude toward sex trafficking as a way to understanding their personal vulnerability to trafficking. A semi-structured questionnaire was administered in 2004-2005 to a classroom random sample of 689 adolescents in the age range of 16-20 years. The results show that in-school adolescents are vulnerable to sex trafficking due to poverty (77.2%); unemployment (68.4%); illiteracy (56.1%); and low social status (44.5%). Students in co-ed schools showed higher knowledge and awareness of the serious health consequences of trafficking (Afr J Reprod Health 2009; 13[2]:33-48)