As an essential part of close relationships, social support is a dynamic interactive process. This paper aims to simultaneously investigate social support‐seeking and provision behaviours using the Actor–Partner Interdependence Model (APIM). Ninety‐two friendship dyads participated in this study. Supportive versus negative friendship qualities were used to predict different support‐seeking and support‐provision behaviours during an experimental task. Cultural and gender variations were also examined. Results showed that self‐reported friendship qualities influence support‐seeking and provision behaviours intrapersonally and interpersonally. Female participants were more likely to provide emotion‐focused support than were male participants. After accounting for friendship qualities in the dyads, there was no evidence of cultural group differences on support‐seeking or provision behaviours among same‐sex friends. These results demonstrate the conceptual and empirical advantages of using APIM to unpack cultural and gender variations in social support processes.