Abstract: This study was carried out in the study area between July to August, 2010 with the aim of determining sexual behaviours among adolescents enrolled to community secondary schools. Quantitative data for the study were collected through interviews with 202 students using a pre-tested semi- structured questionnaire. Furthermore, eight (8) Focus Group Discussions (FGDs) with students and in-depth interview with some key informants were also carried out to collect qualitative information. Findings from the study revealed that despite majority of adolescents were aware of some issues related to Sexual and Reproductive Health (SRH), however, levels of sexual activity and risky sexual behaviours among them were unacceptably high. Sixty three percent of sampled adolescents had ever experienced sex, with age at first sex by half of them (51.2%) being 15 years and below. Furthermore, of the respondents who had ever experienced sexual intercourse, 22% had multiple sexual partners, 21% had ever had sex with casual partner, and 36% didn’t use condom in their last sexual encounter. Main factors for prevalence of sexual activity among adolescents in the study population included failure by adolescents to control their sexual emotions, peer pressure, financial/material gain, cultural practices, and living arrangement. Based on these findings, recommendations to improve the situation have been indicated