Aims and objectives: The existing literature indicates that shared book reading is associated with benefits in children’s home language development. Parents play a significant role in shaping children’s language outcomes. The purpose of this study was to investigate the relations among the quality of parents’ shared book reading, children’s language output, receptive vocabulary, and expressive vocabulary outcomes in the home language of dual language learners (DLLs) to inform book reading practices that can support DLLs’ early home language development. Methodology: 36 Mexican American (43–67 months) and 31 Chinese American (38–70 months) DLLs and their mothers, who were home language dominant, were recruited from Head Start programs, which are federally funded programs that provide early childhood education to low-income children, in Northern California. Data and analysis: Utterances produced by the parents during parent–child shared book reading were coded for cognitive demand levels. DLLs’ home language expressive vocabulary and receptive vocabulary and information about parents’ demographics and parent–child shared reading frequency were collected. Correlations and hierarchical regression analyses were computed. Findings/conclusions: The findings demonstrated possible cultural differences in mothers’ book reading quality regarding cognitive demand. Although maternal statements and questions were not significantly associated with DLLs’ home language receptive and expressive vocabulary for both groups, asking yes/no, referential, and inferential questions were more likely to evoke more language output from DLLs. Originality: This study extends the literature on home language development of low-income DLLs during parent–child shared reading, as only a few studies have investigated the significance of shared reading in the home language. Significance/implications: The findings of this study yield important implications for parents’ shared reading practices with low-income DLLs. Using all levels of cognitively demanding speech and encouraging DLLs to talk during shared reading may benefit their home language development.