Analysis of 676 parent-child pairs reveals that mindful parenting practices predict lower child irritability scores over time, with a standardized effect size of -0.166. The relationship appears unidirectional—mindful parenting influences child emotional regulation, but children's irritability levels do not significantly affect subsequent parental mindfulness. This finding adds quantitative support to attachment theory's emphasis on parental modeling in emotional development. The research is particularly relevant as children enter formal schooling, when emotional regulation skills become critical for academic success and peer relationships. However, the modest effect size suggests mindful parenting is one factor among many in child emotional development. The study's strength lies in its longitudinal design tracking the same families over time, though the reliance on parental self-reporting introduces potential bias. For parents seeking evidence-based approaches to support their child's emotional growth, this research reinforces that cultivating present-moment awareness and non-reactive responses during parent-child interactions may yield measurable benefits. The unidirectional nature of the relationship also suggests that even challenging child behaviors need not derail mindful parenting efforts, as the influence flows primarily from parent to child rather than the reverse.