Given the scarcity of studies addressing substance consumption and its relationship with attachment styles and early maladaptive schemas in adolescents, the present study is proposed. Aims of this study are to analyze the relationship among attachment styles, early maladaptive schemas, and substance use; test the predictive role of attachment styles on substance use; and observe the mediating role of early maladaptive schemas in the relationship between attachment and substance use. The sample consisted of 1533 adolescents from Ecuador (53.9% males) aged between 14 and 18 years (M = 15.76; SD = 1.25). The attachment styles of security, value to parental authority, parental permissiveness, parental interference, self-sufficiency and resentment against parents, childhood trauma, and family concern predict substance use (tobacco, alcohol, tranquilizers/sedatives or sleeping pills, hashish or marijuana, cocaine, GHB or liquid ecstasy, ecstasy, amphetamines/speed, hallucinogens, heroin, inhalants/volatiles), and the mediating role of early maladaptive schemas is confirmed (explained variance up to 33.33%). Identifying risk or vulnerability factors, such as attachment and early maladaptive schemas related to substance consumption, is especially relevant for designing and implementing preventive interventions in the adolescent population.