The quality of parent-infant interaction is crucial for infant development, and the postpartum
period is considered particularly important for subsequent developmental pathways. Parental
mentalizing has been identified as a key component influencing parental behavior. Yet, no meta-
analysis has specifically focused on the link between parental mentalizing and observed parental
behavior during parent-infant interaction in the first year postpartum. The present study ad-
dresses this gap by conducting a meta-analysis of 20 studies involving mothers and their 0–12
months old infants. A three-level random effects analysis, encompassing 133 individual effect
sizes and 1990 participants, revealed a small, positive overall effect size (r = 0.20). Moderator
analyses investigated the influence of study methodology (e.g., offline versus online assessment of
mentalizing, free-play interaction versus non-free play), sample and study characteristics on effect
size. Using meta-regression, significant moderators were maternal SES risk-status and study
publication year, while study methodology and other sample and study characteristics did not
moderate the association. The study advances our understanding of parental mentalizing and
parenting behavior in the postpartum period, providing methodological considerations for
mentalizing assessment. Results are discussed in terms of implications and recommendations for
future research.