Reading self-beliefs, comprising self-concept and self-efficacy, play a pivotal role in shaping students' learning engagement and learning outcomes. However, existing literature on the self-beliefs of school-entry students primarily originates from Western contexts, and the exploration of differences in self-beliefs, engagement in learning, and their impact on reading performance among L1 and L2 learners remains uncharted territory. This dearth of knowledge leaves us questioning whether self-concept and self-efficacy function uniquely in shaping the reading development of L1 and L2 children. Research Findings: By conducting multigroup SEM analysis, this study found no significant differences in self-efficacy or self-concept between L1 and L2 Chinese first-grade students. However, it did reveal distinct patterns in their impact: In L1 students, self-efficacy and self-concept predict learning engagement, with self-concept having a stronger influence on reading performance. Conversely, for L2 students, self-efficacy primarily affects their learning engagement, which indirectly impacts reading performance. Practice or Policy: This study enhances our understanding of different roles of self-beliefs in L1 and L2 learning and offers pedagogical insights for language teaching in countries with both ethnic minority and local populations.