Although several studies have addressed the relations between perceived parental warmth and social behaviours, few have distinguished their between‐ and within‐person effects or explored their within‐person mediating mechanisms. This study examined the transactional relations among perceived parental warmth (i.e. maternal warmth and paternal warmth), children's self‐esteem and children's positive/negative social behaviours (i.e. prosocial behaviour and delinquent behaviour) along with the mediating role of self‐esteem after disentangling between‐ and within‐person effects. A total of 4315 Chinese elementary children (44.9% girls; Mage = 9.93 years, SD = 0.73) completed relevant measures on four occasions employing 6‐month intervals. Results of random‐intercept cross‐lagged panel models showed that (a) perceived parental warmth reciprocally and positively predicted prosocial behaviour and self‐esteem; (b) perceived paternal warmth reciprocally and negatively predicted delinquent behaviour; (c) self‐esteem reciprocally predicted prosocial and delinquent behaviour; (d) perceived maternal warmth reciprocally and positively predicted prosocial behaviour through self‐esteem; (e) perceived parental warmth reciprocally and negatively predicted delinquent behaviour through self‐esteem; and (f) perceived maternal and paternal warmth differed in their relations with prosocial and delinquent behaviours through self‐esteem. These findings illuminated the complicated longitudinal within‐person interactions among perceived parental warmth, self‐esteem, and social behaviours, the specific mediating mechanism of self‐esteem, and the differing results associated with perceived maternal and paternal warmth, all of which yield significant implications for assessments and early interventions aimed to promote positive social behaviour.