This study explored the extent to which loneliness of Indonesian and Chinese adolescents was predicted by their intimacy and conflict with friends and parents. The total sample included 1,833 thirteen- and fifteen-year-old adolescents recruited from urban schools. Boys reported more loneliness than girls, and Chinese boys reported more loneliness than Indonesian boys. Indonesian adolescents reported less intimacy with friends, more intimacy with parents, and more conflict with peers and parents than did Chinese adolescents. Consistent with expectations, loneliness was predicted primarily by low intimacy with friends for Chinese adolescents and by low social preference for Indonesian adolescents. Whereas low intimacy and conflict with parents predicted loneliness for adolescents in both countries, these effects were stronger for Chinese than Indonesian adolescents. These findings suggest that experiences of loneliness across cultures vary as a function of the relative salience of qualities of peer and parent relationships.