Background: Early childhood is essential for the rapid development of self-regulation systems, shaped by brain maturation and parental discipline. Inadequate discipline can hinder this development, leading to behavioral, social, and long-term negative outcomes. Objective: This meta-analysis synthesizes research conducted over the last two decades, a period marked by societal changes such as globalization and social media, to examine the association between parental discipline and self-regulation in early childhood. Methods: A systematic literature search was conducted using ScienceDirect, PsycINFO, Web of Science, Medline, and Scopus. Studies from 2000 to 2022 that focused on cross-sectional, survey-based analyses of parents and non-clinical children in toddlerhood and early childhood (aged 2-5) were included. This review involved 28 studies with 27,285 children and caregivers. Study sample sizes ranged from 55 to 12,474. The analysis followed PRISMA guidelines, extracting and synthesizing data accordingly. Results: The findings revealed small but consistent correlations between parental discipline and children's self-regulation. Both positive and negative discipline exhibited similar effect sizes, though with opposite outcomes. Negative discipline was linked to lower self-regulation, while positive discipline was associated with higher self-regulation. Additionally, the association between negative discipline and self-regulation diminished with child's age, as shown by meta-regression results. Conclusions: This study confirms that both forms of parental discipline are associated with children's self-regulation. Positive discipline fosters better outcomes, while negative discipline is associated to lower self-regulation. Although these effects are small, they highlight the importance of parental practices while acknowledging that other factors also contribute to children's self-regulation development.