This study investigated the impact of parental involvement on school readiness, focusing on the mediating role of preschoolers' self-efficacy. The research utilized a cross-sectional survey design with 1,000 preschool children from seven public kindergartens in Beijing, China. Structural equation modelling was employed for data analysis. The findings indicate that parental involvement, including its sub-dimensions of home-preschool conferencing, preschool-based involvement, and home-based involvement, significantly enhances preschoolers' self-efficacy and school readiness. This encompasses various readiness aspects such as physical and psychological, life, social, and learning readiness. Furthermore, a bootstrap test indicated that preschoolers' self-efficacy fully mediated the relationship between parental involvement and physical and psychological readiness, and school readiness.