Relations between interior self-knowledge and (a) imaginary companion (IC) status and
(b) theory of mind (ToM) abilities were investigated in a sample (N = 80) of 4- to 7-
year-olds. Interior self-knowledge was assessed in terms of the extent to which children
acknowledged that they (rather than an adult) were the authority on unobservable
aspects of themselves (e.g., dreaming, thinking, hunger). Compared with children without
an IC, those who possessed a parentally corroborated IC ascribed less interior selfknowledge
to an adult, with a trend for them to assign more interior self-knowledge to
themselves. Children’s interior self-knowledge judgments were not associated with their
ToM performance. IC status was also unrelated to ToM performance. We consider how
having an IC may provide children with opportunities to distinguish between knowledge
that is inaccessible to an external observer and that which an external observer may
glean without being told.