The strength-based approach argues that promoting adolescents’ developmental assets would contribute to their well-being. This study investigated meaning in life (MIL) as one of such developmental assets. Based on the annual assessment of 3,328 Hong Kong Chinese adolescents from Grade 7 to Grade 12, we found that MIL at Grade 7 predicted heightened hedonic well-being and reduced risk behaviour at Grade 12; slower decrease in MIL from Grade 7 to Grade 11 predicted heightened hedonic well-being and reduced risk behaviour at Grade 12 with the initial level of outcomes controlled. Findings highlight the importance of MIL as a developmental asset fostering adolescent well-being. Implications of the findings for advancing theory of MIL and social work practice are discussed.