Due to the growing number of sexually active adolescents worldwide, adolescent sexual development is critical. The purpose of this study was to look at the factors that influence sexual development in adolescents at Niger Delta University's Faculty of Nursing Sciences in Amassoma, Bayelsa State. Researchers used a descriptive survey design. Two research objectives were established to guide the study's course. The study's sample size was 160 adolescents chosen using a random sampling technique. The study included a self-structured questionnaire. The instrument's face and content validity were assessed. The test-retest approach was employed to determine the reliability of the questionnaire. According to the findings of this survey, adolescents have adequate awareness of sexual development because the majority of the respondents (152%) had heard about it. Friends 68(42.5%), social media 40(25%), school 32(20%), and parents 28(17.5%) were the sources of knowledge about sexuality development. Sex hormones were discovered to impact sexuality development in adolescents 130(81.25%), and estrogens and testosterones were revealed to be responsible for primary and secondary sexual characteristics in adolescents 90(56.25%). Furthermore, peer pressure impacts teenage sexuality development through counseling from peers 110(68.75%), dating relationships 120(75%), drinking and clubbing 116(72.5%), and sexual language usage 100(62.5%). However, psychosocial factor influencing sexuality development in adolescents includes; anxiety/depression 90(56.25%) self-esteem (low/high self-esteem) 83(51.88%), peer pressure 140(87.5%), parental influence 102(63.75%), alcoholism 104(65%), drug addiction 99(61.88%), pornography/masturbation 83(51.88%), religiosity 92(57.5%), culture 100(62.5%), mass media 121(75.63%) and nutrition 82(51.25%). In conclusion, the effects of hormones and psychosocial variables were identified as predictors of sexuality development in adolescents. It is Friends 68(42.5%), social media 40(25%), school 32(20%), and parents 28(17.5%) were the sources of knowledge about sexuality development. Sex hormones were discovered to impact sexuality development in adolescents 130(81.25%), and estrogens and testosterones were revealed to be responsible for primary and secondary sexual characteristics in adolescents 90(56.25%). Furthermore, peer pressure other factors have impacts on sexual development. However, it is recommended that Institutions should employ and retrain counselors through in-service training programs, capacity development seminars, and refresher courses on sexual behavior counseling among adolescents.