This study examined the within- and cross-language relationships between intrinsic language learning motivation, home literacy environment (shared book reading, parental literacy involvement, and parent perceived child literacy interest), and receptive vocabulary in 185 bilingual preschoolers and 233 primary school children in Singapore. Age differences were also examined. Unlike the motivation decline commonly observed in middle childhood, the primary school children demonstrated higher levels of intrinsic motivation than the preschoolers in both English and the second language (L2). Results showed a motivation gap between English and children's L2 in primary school children but not in preschoolers. The hierarchical regression results revealed that intrinsic motivation and the three facets of home literacy environment (HLE) were differentially involved in receptive vocabulary across languages and age groups. Within-language relations showed that intrinsic motivation only predicted receptive vocabulary in English among primary school children, but not among preschoolers. Among primary school children, parent perceived child literacy interest in L2 was the only significant predictor of L2 receptive vocabulary; among preschoolers, shared book reading was the only significant predictor. Cross-language relations revealed that parental literacy involvement in English negatively predicted L2 receptive vocabulary in primary school children, and there were no L2 effects on English receptive vocabulary.