Longitudinal studies published between 1980 and 2001 (N = 10) are reviewed for evidence that the religiosity of adolescents is causally related to their sexual behaviors. Results indicate that religiosity delays the sexual debut of adolescent females. Findings are mixed for adolescent males. Although only half of the studies examined the effects of race and ethnicity, results of these studies reported similar effects for White and Black adolescents. These findings are discussed in light of their implications for researchers, educators, policy makers, and others concerned with adolescent sexual health and well-being.