This prospective, longitudinal study investigated the moderating role of pubertal timing on reciprocal links between adolescent appraisals of parent-child relationship quality and girls' (N = 1,335) and boys' (N = 1,203) cigarette and alcohol use across a 12-month period. Reciprocal effects were found between parent-child relations and on-time maturing boys and girls' cigarette and alcohol use, after estimating stability in these constructs across time. Parent-child relationship quality was associated with increased alcohol use 12 months later for early maturing girls. Cigarette and alcohol use were associated with increased problems in the parent-child relationship for late maturing girls. No effects were observed for early and late maturing boys in the pathways between parent-child relationship quality and substance use. Pubertal timing moderated the pathway linking parent-child relationship quality with cigarette use 1 year later such that the association was stronger for late maturing girls compared with early and on-time maturing girls. The findings indicate interplay between the psychosocial aspects of maturation, family relationships, and adolescent substance use and highlight possible gender-specific influences.