The major purpose of this study was to assess the relationships among adolescents’ Social mediarnusage, sexual behavior and risk perception. A descriptive survey was employed as a studyrndesign. Questionnaire was used to gather data from a random sample of 300 (150 male and 150rnfemale) students of grade 9 th through 12 th in the selected five private high schools of Bole sub-rncity. Descriptive statistics, Chi-square, t-test, ANOVA and correlations were used to analyzernquantitative data. Descriptive statistics revealed that entertainment, communication with peoplernfar away and making companionship (34.3%, 20% & 16%) were the major reasons to schoolrnadolescents’ social media usage respectively. Weak positive correlation was found betweenrnsocial media usage and sexual behavior [r (298) = .222, P < .05]. However, sexual behaviorrnwas moderately correlated with the frequency use of social media sites used [r (298) = .694, P=rn