Background: Marijuana is the most commonly used illicit substance among adolescents. There is paucity in the literature on the relationship between school sports participation and marijuana use. Therefore, the purpose of this study was to assess the relationship between school sports participation and recent marijuana use, past year marijuana use, perceived harm, perceived peer disapproval, and ease of marijuana access among males and females. We defined past year marijuana use as having smoked marijuana in the past year of survey completion and recent marijuana use as having used marijuana in the past 30 days of survey completion. Methods: We performed a secondary analysis of 2013-2014 Parents’ Resource Institute for Drug Education Survey data including 37,616 7-12th grade students. Chi-square analyses and odds ratios were performed. Results: About 15% of students indicated that they used marijuana within the past 30 days of survey completion. Nearly one-fourth (23.4%) of students reported recently using marijuana in the past year of completing the survey. Males were more likely to report recent marijuana use and past year marijuana use compared to their female counterparts. Results revealed males and females who reported participating in school sports often/a lot were less likely to report recent or past year marijuana use than those who never/ seldom participated in school sports. Perceived harm, peer disapproval, and ease of access also differed based on school sports participation for males and females. Conclusions: Sports participation had a protective effect against marijuana use. Increasing peer disapproval and perceived harm while reducing perceived ease of access may be beneficial in reducing marijuana use. Initiatives to reduce substance use among 7-12th graders should focus on increasing pro-social activities, specifically school sports participation.