Mentalizing, conventionally defined as the process in which we infer the inner thoughts and intentions of others, is a fundamental component of human social cognition. Yet its role, and the nuanced layers involved, in real world social interaction are rarely discussed. To account for this lack of theory, we propose the interactive mentalizing theory (IMT) -to emphasize the role of metacognition in different mentalizing components. We discuss the connection between mentalizing, metacognition, and social interaction in the context of and social cognitions and which is central to all other components of mentalizing including: (ii) first-order mentalizing-inferring the thoughts and intentions of an agent's mind; (iii) personal second-order mentalizing-inference of other's mentalizing of one's own mind; (iv) Collective mentalizing: which takes at least two forms (a) vicarious menagent) and (b) co-mentalizing: mentalizing about an agent in conjunction with others' mentalizing of that agent (i.e., conforming to others beliefs about another agent's internal states). The weights of these four elements is determined by metacognitive insight and confidence in one's own or another's mentalizing ability, yielding a dynamic interaction between these circuits. To advance our knowledge on mentalizing during live social interaction, we identify how these subprocesses can be organized by different target agents and facilitated by combining computational modeling and interactive brain approaches. (C) 2020 Elsevier Ltd. All rights reserved.