Effects on adjustment of biological maturation and social timing were compared using data from a longitudinal sample of 335 young adolescents, who were followed from the sixth through eighth grades. Biological maturation was estimated from the relative timing of the adolescent growth spurt. Social timing was assessed by grade in school. Five adjustment constructs were examined: school achievement (course grades in five subjects), family relations (a 17-item scale), peer relations (a 10-item scale), body image (an 11-item scale), impulse control (an 8-item scale), and psychopathology (an 11-item emotional tone scale and an 11-item general psychopathology scale). All but one adjustment construct showed grade effects, but only three of the six constructs showed pubertal timing effects. There were no grade by pubertal timing effects. Although there were gender differences for some of the adjustment constructs, there were no gender by pubertal timing effects. The results are discussed in terms of the life-span developmental perspective.