Siblings’ imitation as a learning strategy and associations with social-cognitive skills was investigated during a teaching session in 60 siblings dyads (M age older siblings = 75.9 mos; M age younger siblings = 49.4 mos). The data consisted of videotaped sibling teaching sessions collected at home or school; the older sibling teacher was taught how to construct a tractor by a research assistant and then had to teach their younger sibling. Using videotapes and transcripts, the coders identified the sequences of imitation and then coded the type of imitation (verbal, nonverbal, spontaneous, deferred), responses (i.e., correction, positive/neutral, negative, not attending, off-task), and functions (i.e., clarification, agreement, disagreement, off task) of imitation. The teaching sessions were also rated for degree of learner involvement and task completion. The coding scheme was adapted from Howe, Rosciszewska, and Persram (2017) and Howe and Leach (in preparation). To measure teachers’ social-cognitive skills (i.e., second-order false-belief, interpretive understanding), different scenarios were enacted (Astington, Pelletier, & Homer, 2002; Howe, Recchia, Della Porta, & Funamoto, 2012). Five main sets of findings were apparent. First, the findings revealed that learners employed more nonverbal imitation in comparison to verbal imitation. In contrast, teachers employed no verbal imitation and only little nonverbal imitation. Learners’ imitated spontaneously after the teacher performed an action or said a word. Second, for the teaching responses, teachers employed more positive/neutral and corrective responses than not-attending and off-task responses to learners’ imitation. Third, during the construction task, learner’s involvement during the teaching session was positively and significantly associated with their use of verbal and nonverbal imitation. Fourth, learners used more clarification and agreement than disagreement functions while imitating. However, task completion was not significantly correlated with learners’ imitation. Fifth, teachers’ social-cognitive skills were not significantly correlated with learners’ imitation, learner involvement or task completion. Findings are discussed in relation to the literature on siblings’ imitation and teaching, theories on teaching, siblings’ cognitive skills and the social functions of imitation.