Introduction: early sexual debut is common among young people and it has several sexual and reproductive health consequences. But, its burden and the associated factors leading to this behavior haven't received due attention. The main purpose of this study was to investigate the prevalence and associated factors of sexual debut in the preparatory and high school students of Aksum town.

Methods: a school-based quantitative cross-sectional study design was used for this research work. A total of 519 preparatory and high school regular students participated in the survey. The sample population was obtained by using a simple random sampling technique from each schooling proportion with their number of students. Data, that were collected using self administered questionnaires, were entered into EpiData 3.02 and analyzed in SPSS 22.0. Results were presented using frequencies, tables and graphs. Statistical significance was declared at a P-value <0.05.

Results: of the total participants, 266 (51.3%) were males. The age of the participants ranged from 13 to 23 years with a mean age of 16.3 ± 1.47 years. Of the total participants, 137(26.2%) had sexual experience, among which 119 (87.5%) had an early sexual debut at an average age of 13.7 + 1.4 years. Factors that were found to be significantly associated with an early sexual debut were gender (AOR=3.41; 95% CI: 1.54, 6.99), residence (AOR=0.44; 95% CI: 0.27, 0.81), alcohol drinking (AOR=5.5; 95% CI: 2.2, 14.8), cigarette smoking (AOR=3.3; 95% CI: 2.3, 7.5), exposure to pornography, such as reading/seeing pornographic materials (AOR=7.4; 95% CI: 4.4, 11.78), living arrangement for educational purpose (AOR= 0.43; 95% CI: 0.13, 0.89), grade (AOR=0.38; 95% CI: 0.06, 0.68) and monthly living allowance (AOR=0.419; 95% CI: 0.2, 0.9).

Conclusion: history of early sexual debut, gender, place of residence, alcohol drinking, cigarette smoking, exposure to pornography, and living arrangement for educational purpose, grade and monthly living allowance were significant predictors of an early sexual experience.