Young children’s ability to learn something new from a third-party interaction may be related to the ability to imagine themselves in the third-party interaction. This imaginative ability presupposes an understanding of self–other equivalence, which is manifested in an objective understanding of the self and an understanding of others’ subjective perspectives. The current study measured imitative learning of a novel action seen only in a third-party interaction, mirror self-recognition, and perspective taking in a group of 48 18- to 20-month-olds. Patterns of performance suggest that understanding self–other equivalence is related to third-party learning.