Imitation is important in social life, manifesting in various forms and serving diverse functions. This chapter concerns socially oriented imitation, wherein the imitator adopts others’ arbitrary or idiosyncratic behaviors primarily for social reasons. While this form of imitation impacts dyadic interactions, it’s also observable by third parties. We review evidence concerning third-party inferences from imitation across the lifespan, spanning from infancy to adulthood. We propose that a simple concept of social affiliation, embedded within an intuitive (naïve) psychological theory, accounts for the pattern of inferences drawn from observing imitation. Essentially, observers assume that imitators, by either imitating or not, reveal whether they adopt concern for the models’ utilities, encompassing their welfare and values. Young observers typically draw positive inferences from such imitative behaviors. However, as observers mature and master understanding of social dynamics, their inferences become increasingly nuanced. They take into account factors like intention, mutual knowledge, social skills, theory of mind, and social strategies. Consequently, this can lead observers to form negative inferences about the imitators and express a preference for non-imitators or counter-imitators. Our proposed explanation sheds light not only on inferences from third-party or first-party mimicry but also more broadly on the social inferences that guide our interpersonal interactions.