This study examined relations of affinity for solitude with social-behavioral, academic, and psychological adjustment in Chinese children and adolescents. The participants included 3,417 students (1,714 boys) in fourth, sixth, and eighth grades (M[subscript ages] = 10, 12, and 14 years, respectively) in China. Data on affinity for solitude were collected from students' self-reports and data on adjustment were collected from multiple sources. The results showed that whereas affinity for solitude was negatively associated with social competence and academic achievement and positively associated with behavioral problems in Grade 4, the associations were weaker or nonsignificant in Grade 6. Moreover, affinity for solitude was positively associated with academic achievement and negatively associated with behavioral problems in Grade 8. Affinity for solitude was negatively associated with psychological adjustment in general, but the associations were weaker in higher grades. The results indicate that the functional meaning of affinity for solitude may differ across developmental periods. Parents, teachers, and professionals should be aware of the different implications of affinity for solitude in childhood and adolescence and use different strategies to support children and adolescents who display affinity for solitude.