Adolescence is an important developmental period when they get involved in sexual activities with their peers, which have the tendency to expose the parties involved to risky sexual behaviours. This study investigated peer sexual behaviours as a correlate of secondary school adolescents sexually risky behaviours in Anambra State. One research question guided the study, while one null hypothesis was formulated and tested at the 0.05 level of significance. The design for the study was correlational survey research. The sample comprised 1,200 students drawn from a population of 19,048 SS2 adolescents in public secondary schools. A standard instrument, the "Adolescent Sexual Behaviour Index," developed by Hansen, Paskett, and Carter (1999), was used for data collection. The internal consistency reliability coefficient for the instrument was 0.86. Data was collected through direct delivery of the instrument to the respondents and analysed using the Statistical Package for Social Sciences (SPSS). The research question was answered using Pearson Product Moment Correlation Coefficients, while the null hypothesis was tested using a t-test for significant correlation. The findings of the study revealed that there is a low positive relationship between sexual behaviour and sexual risk behaviours among public secondary school students in Anambra State. The findings further revealed that the relationship existing between peer sexual behaviour and sexual risk behaviours of secondary school adolescents in Anambra State is significant. Based on the findings of the study, it was recommended that school management set up school health programmes that can help young people adopt lifelong sexual behaviours that support their health and well-being, including behaviours that can reduce their risk for HIV and other STDs.