The social responses of 48 7‐ and 10‐month‐old infants were analysed and compared in the context of dyadic and triadic situations. In the dyadic situation, infants’ reactions to a sudden 1 min still face adopted by a social partner in a face‐to‐face interaction were recorded. In the triadic situation, infants’ monitoring of a social partner in various situations of object exploration was recorded. Results indicated that specific responses in a dyadic context correlate with responses expressed by the infant in a triadic context. At either age, infants that demonstrated attempts to re‐engage the experimenter during the still‐face episode in the dyadic situation were also those who manifested the most signs of joint engagement, attention following and attention monitoring in the triadic situation. These findings are interpreted as the demonstration of a developmental link between dyadic and triadic social competence in infancy.