This study explored the relationship between social media exposure and substance abuse among adolescent secondary school students in Delta State, Nigeria. Two (2) research questions and two null hypotheses guided the study. The study adopted correlational method of ex-post facto research design. The target population of this study comprises of all public secondary school (2) students in the 25 local government areas of Delta State with a sample size of 500 students from the three Senatorial District in Delta State. This sample represents 10% of the population, drawn through the multi-stage procedure and stratified random sampling technique. The instrument used for data collection was an adopted questionnaire, which include social media scale (SMS) developed by Osharive (2015) and Drug abuse scale (DAS) developed by Aleke (2013). The instrument had a reliability coefficient of .78 and .69 for social media scale and drug abuse scale respectively. Correlation was used to answer research questions while the two hypotheses were tested using regression model statistics at .05 level of significance. The findings of the study revealed that there is a significant relationship between social media and substance abuse among adolescent students, and also school type has a significant moderating impact in the relationship between social media and substance abuse among adolescent’s students in secondary schools in Delta State. Based on the findings, it was concluded that social media correlated with substance abuse among adolescent’s secondary school students; while it was recommended that parents, educators and members of the community should monitor and guide the students on appropriate use of social media in order to reduce its effect on substance abuse by adolescent students.