Mimicry of appearance or of facial, vocal, or gestural expressions emerges frequently among members of different species. When such mimicry directly relates to affective aspects of an interaction, researchers talk about “emotional mimicry”. Emotional mimicry has been amply documented but its functionality is still debated. Why and when do people mimic the expressions of others, who benefits, the mimicker or the mimicked, and how do they benefit? Which processes underlie emotional mimicry? Is it completely automatic and unconscious or can it (...) be deliberate and conscious? The current Theory Section addresses these questions from different theoretical perspectives. The invited article by Hess and Fischer focused on the role of mimicry in social regulation and social bonding. The invited comment by Krets and Akyüz highlights information gathering and prediction in social interaction. The invited comment by Bernhold and Giles emphasizes vocal communication and its role in interpersonal accommodation. In this editorial, I propose the different theoretical perspectives may be integrated by assuming a multilevel appraisal and response generation mechanism. I also suggest that emotional mimicry research may be broadened by including social learning, vocal imitation, interspecies comparisons, and affective computing approaches. (shrink)