Pregnant and nonpregnant populations in the United States report marijuana as the most commonly used illicit drug. Patterns of marijuana use and psychosocial correlates are unclear among non-treatment-seeking teenage girls. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: The objective of this study was to use cross-sectional data to examine the psychosocial correlates of recent marijuana use among a sample of 646 pregnant and nonpregnant adolescent girls presenting to urban primary care clinics (mean age=15.6years, SD=1.9years; 65% African American; 8.8%pregnant). In Poisson regression analysis, frequency of marijuana use was significantly associated with greater likelihood of pregnancy (incident rate ratio [IRR], 1.30; 95% CI, 1.03-1.65), alcohol use (IRR, 1.11; 95% CI, 10.08-1.14), condomless sex (IRR, 1.95; 95% CI, 1.61-2.37), parents' drug use (IRR, 1.04; 95% CI, 1.02-1.05), and negative peer influences (IRR, 1.12; 95% CI, 1.10-1.16). Marijuana use among adolescent girls in this sample was associated with a number of risk behaviors as well as parental and peer influences. Culturally sensitive screening and intervention approaches for marijuana use among adolescent girls should address multiple individual, relationship, and community factors, to prevent unwanted pregnancy as well as to reduce marijuana use during this vulnerable time.