INTRODUCTION: Many adolescents engage in risky sexual activity without protection as shown by recent WHO report and this practice commonly resulted in sexually transmitted infections (STIs) including human immunodeficiency virus (HIV), unwanted pregnancy and unsafe abortion. OBJECTIVE: This study is intended to describe the sexual behaviour of students in senior secondary schools in Nnewi North and South LGAs of Anambra State, South-eastern Nigeria and to describe their attitude toward contraceptive use for the prevention of pregnancy and STIs. METHOD: A descriptive cross-sectional study which employed multi-stage and proportionate sampling techniques was conducted. RESULT: A total of 394 students, age range of 12 – 24 years with mean of 17 ± 1.6years were studied. 95 (24.1%) admitted to previous sexual exposure with mean age at sexual debut of 12 ± 3.6 years. More than half of them had multiple sex partners and learnt about sex from the media. 74.7% of the respondents did not use condom during their first sexual exposure and 83.3% of those who had been pregnant or got someone pregnant terminated the pregnancy. CONCLUSION: This study shows a need for better government and societal commitment to adolescent reproductive health issues and incorporation of school-based interventions relating to sexuality education into school curriculum.