Background/Purpose Few studies have been published regarding sexual risk behaviors among African adolescents. In Ghana, there is a lack of studies to gain better insight into the sexual behavior of adolescents. Using national level data, this study examined the association between age-of-initiation of sex and 4 sexual behavior variables when considering grade. Method We utilized data from the 2008 Ghana Global School-based Student Health Survey. The sample size was 7, 137 senior high school (SHS) students. Selected sex related variables were dichotomized for complex sample table analysis. Analysis/Results There was a significant association between age-of-initiation of sex and 2 or more lifetime partners (X2 =422.7, F=569.9, df1=1, df2=251, p<0.001), age-of-initiation of sex and gotten/got someone pregnant (X2 =87.0, F=83.1, df1=1, df2=251, p<0.001) and, age-of-initiation of sex and STI infection (X2 =8.3, F=11.3, df1=1, df2=251, p=0.001). The odds of having initiated sex before age 13 were 8.8, 4.5 and 1.8 times greater, respectively. There was no association between age-of-initiation of sex and condom use during last sex act. Odds ratios were not significantly different when considering grade level except for age-of-initiation of sex by lifetime partners. The odds were significantly greater for SHS-1 students (14.4) with 2-plus lifetime partners to have initiated sex before age 13 compared to SHS-2 (5.9) students. Conclusions Ghanaian adolescents' age-of-initiation of sex is significantly associated with engagement in sexual risk-taking behaviors leading to negative health outcomes. Further investigations are necessary to establish predictors of early sexual initiation in order to address sexually risky behaviors/outcomes.