The self is not static. Our identities change considerably over development and across situations. Here, we propose one novel cause of self-change: simulating others. How could simply imagining others change the self? First, when simulating other people's mental states and traits, individuals access self-knowledge; they do so while concurrently considering information about the other person they are trying to understand. Second, episodic and semantic knowledge is malleable and susceptible to incorporating new, postevent information. If self-knowledge is similarly malleable, then simulation may change self-knowledge such that it incorporates information about the simulated person (i.e., "postevent information"). That is, simulation should render the self more similar to the simulated other. We test this hypothesis in 8 studies. In each study, participants (a) recalled personal information (e.g., traits and episodic memories), (b) simulated other people in similar contexts, and (c) re-recalled personal information. Results consistently demonstrated that simulating others changed self-knowledge, such that the self becomes more similar to the simulated other. This effect occurred for both traits and memories, spanned self-report and linguistic measures, and persisted 24 hr after simulation. The findings suggest that self-knowledge is susceptible to misinformation effects similar to those observed in other forms of semantic and episodic knowledge. (PsycINFO Database Record (c) 2019 APA, all rights reserved).