Family socioeconomic status (SES) has been frequently linked to children’s early development. Treating SES as an aggregated variable has many issues, as different components of SES may relate to child outcomes through divergent mechanisms. The purpose of the study was to examine whether parents’ engagement in home learning activities and children’s participation in extracurricular activities (EAs) would function as pathways through which individual SES components related to children’s school readiness. A total of 588 families with preschool-aged children were recruited from Guangdong province in China. Children’s receptive vocabulary, Chinese reading, and early math skills were individually assessed at three time points, and children’s social skills were rated by parents. Parents reported their engagement in home learning activities with children and their children’s participation in EAs. The results showed that all three components of family SES were related to multiple aspects of children’s school readiness, but through different pathways. Parental income was related to children’s school readiness through EA participation only; parental education and occupational status were associated with school readiness via both parental engagement and child EA participation. The findings suggest that considering SES components separately will produce a more nuanced understanding of the divergent pathways through which family SES may relate to children’s school readiness. Chinese government may provide parent education programs focused on cognitive stimulation for low-SES families to promote children’s school readiness. Furthermore, the government needs to ensure children’s equal access to EAs to prevent increasing the developmental gap among children from discrepant socioeconomic backgrounds.