In recent developmental research, sleep-wake patterns and preferences, in other words Morningness-Eveningness, have been shown to be related to various kinds of problem behavior. Previous research on adolescents has demonstrated that individuals with a sleep-wake preference toward staying up late in the evening and arising late in the morning (i.e., Eveningness), are more likely to face problems in development. Accordingly, Eveningness has been proposed as a risk factor in development, but through processes which researchers have not been able to fully explain. The present dissertation focuses on the relationship between Morningness-Eveningness and developmental patterns across contexts in adolescence. Links between Morningness-Eveningness, and negative adjustment, life style, personality characteristics, family relationships, peer networks, and school achievement, are discussed within an interactionistic framework. Also, factors that might explain and/or moderate these associations are elucidated. The empirical material stems from two cohorts of 8th grade adolescents in a middle size Swedish community. Eveningness is proposed to be a concurrent marker of risk behavior. However, there seems to be different kinds of Evening types that encounter different kinds of problems. Also, the present findings do not support the notion of Morningness being protective. How temporal patterns in general, and Eveningness in particular, are connected to other behaviors is emphasized as important knowledge for stemming negative developmental processes and facilitating positive outcomes.