AbstractTo be a desirable social partner and develop healthy relationships with peers, a child must be able to engage with peers across a variety of contexts. Understanding the factors supporting high levels of social engagement with peers is thereby essential, requiring the development of nuanced and ecologically valid indices of social engagement. Building on recent adult work, the current study explores conversational response time as a novel index of children's social engagement with peers in a dyadic context. This study further explores relationship between conversational response time and children's shyness. Fifty‐six 9‐ to 11‐year‐old children interacted with an unfamiliar peer in an unstructured setting and completed a self‐report measure of shyness. Children's behaviour was coded for their conversational RTs and overall social engagement. Faster conversational RTs were significantly related to children's own social engagement and marginally related to their partners' engagement. Moreover, higher shyness in children's partners predicted faster conversational RTs in children themselves. New directions for using conversational RT as an index of children's social engagement and implications for accounts children's social development are discussed.