The rate of premarital sexual intercourse among adolescents in Nigeria is alarming, despite its prohibition by several
religious groups. This contradiction prompted the question: what is the prevailing relationship between religion, religiosity, and adolescents’ sexual behaviour in the country? This relationship was examined through survey data collected between December 2009 and February 2010 in the Lagos metropolis. A multistage sampling procedure was adopted in selecting 1026 adolescents between 12 and 19 years of age in the metropolis 2 and Logistic regressions techniques were employed in data analysis. Results reveal that religious affiliation is significantly related to only casual sexual relationships among boys at the level of 2 analysis