<p>Sexual abstinence represents a reproductive health-promoting behavior and a better strategy to prevent the risks of early sexual initiation and negative sexual and reproductive consequences among adolescents and young adults (AYAs). However, little is known about factors associated with abstinent behavior in Chad and Cameroon. Therefore, this study investigates the predictors of sexual abstinence behavior among high school AYAs in Chad and Cameroon, using the integrated theoretical framework of adolescent’s sexual abstinence. A total of 1,158 students from high schools aged between 15 and 24 years, selected using the time-location sampling technique in Chad and Cameroon were involved in the study. A self-administered questionnaire composite of Perceived Norms for Delaying Sex Scale, Self-efficacy in Sexual Abstinence Scale, sexual communication, sexual citizenship awareness, parental control and quality of relationship, sexual behavior, and some sociodemographic characteristics was administered. Data analyses were done with statistical software SPSS, v.20 using frequencies, means, and Multinominal logistic regression. Model 1 and 3 were statistically significant in explaining, respectively, primary sexual abstinence and intention to abstain from sex in both countries (<i>p</i> &lt; 0.001), but Model 2 was only statistically significant in explaining secondary sexual abstinence in Chad (<i>p</i> &lt; 0.001). Significant predictors were self-efficacy in sexual abstinence, sexual communication with friends, parental control, quality of relationship with parents, gender, age, educational level, religion and religiosity, father and mother’s level of education, relationship status, exposure to pornography, and sexual citizenship awareness. Educational interventions in promoting primary and secondary abstinence among Chadian and Cameroonian AYAs need to consider these factors.</p>