Adolescent pregnancy (AP) is a significant public health issue. Child maltreatment (CM) represents an established risk factor, yet little is known about the explanatory mechanisms linking the phenomena. Informed by developmental theory, this study prospectively tested seven multi-level, indirect pathways that could plausibly explain the relationship between CM and AP: (1) substance use (polysubstance use and frequency); (2) sexual risk behavior; (3) depressive symptoms; (4) posttraumatic stress disorder symptoms; (5) cognitive dysregulation; (6) pregnancy desire and difficulty expectancies; and (7) age at menarche. Data came from a prospective, longitudinal cohort study of 469 ethnically diverse, nulliparous adolescent females, designed to examine the impact of substantiated CM on reproductive outcomes such as pregnancy and childbirth (265 maltreated and 204 demographically matched comparison adolescents). A multiple-mediator structural equation model was conducted to simultaneously test multiple indirect effects while accounting for confounding variables. Maltreatment had an indirect effect on pregnancy via substance use and higher pregnancy desire/lower perceived difficulty. Findings represent a step towards elucidating pathways linking CM with AP. Recommendations are offered to prevent pregnancy by addressing the pregnancy-specific mechanisms that are part of the maltreatment sequelae.