Students’ learning is deeply rooted in both home and school environments. This necessitates a person-and-context perspective that considers individual, home, and school factors. This study delved into second language learning, an area inherently intertwined with these settings. Utilizing hierarchical linear modeling, the study involved 2,310 fifth-grade English–Chinese bilingual students and 109 teachers across 109 classrooms in 23 Singaporean primary schools where Chinese is taught as a second language. We examined the class compositional effect of Chinese use at home on students’ Chinese language achievement and the cross-level interactions between classroom goal structures (mastery and performance goal structures) and Chinese use at home in predicting Chinese language achievement. Aggregated class-level Chinese use at home exhibited a compositional effect on students’ Chinese language achievement. Additionally, the class-level Chinese use at home strengthened the positive relation between individual students’ home language use and their achievement in Chinese. Moreover, classroom mastery goal structure demonstrated significant moderating effects on the relation between students’ Chinese use at home and Chinese language achievement. While Chinese use at home was positively related to achievement, this relation was weaker in classes with high mastery goal structure and stronger in classes with low mastery goal structure. No main effect or interaction effect concerning classroom performance goal structure was observed. These findings highlight the intricate relation between home language exposure and classroom goal structures. Being surrounded by peers who use the second language often at home may enhance second language achievement. Furthermore, mastery-focused environments may compensate for students with limited second language exposure at home. (PsycInfo Database Record (c) 2024 APA, all rights reserved) Declaración de impacto