Previous research has shown an association between child maltreatment (sexual abuse, physical abuse, neglect, or witnessing interparental violence) and adolescent sexual risk behaviors (SRBs). The mechanisms explaining this association are not well understood, but attachment theory could provide further insight into them. This study examined the relationships between child maltreatment and SRBs and investigated anxious and avoidant attachment as mediators. The sample comprised 1,900 sexually active adolescents (13 to 17 years old; 60.8% girls) attending Quebec high schools. The results of path analyses indicated that neglect was associated with a higher number of sexual partners, casual sexual behavior, and being younger at first intercourse. Anxious attachment mediated the relation between neglect and number of sexual partners, whereas avoidant attachment explained the relation between neglect and number of sexual partners, casual sexual behavior, and age at first intercourse (for boys only). Sexual abuse was directly associated with all three SRBs. Neither anxious attachment nor avoidant attachment mediated these associations. Youth with a history of neglect and sexual abuse represent a vulnerable population that is likely to engage in SRBs. Interventions designed to induce a positive change in attachment security may reduce SRBs among victims of neglect.