A large sample of autistic and non-autistic adults was recruited to investigate whether self-reported beliefs about their own and other people's mindreading abilities were in line with either mindreading deficit accounts of autism or the double empathy problem (DEP) (which proposes mindreading difficulties are relational in autism). Three hundred and forty-eight (139 autistic) participants completed an online questionnaire which asked about autism identification and diagnostic status and their beliefs about their own mindreading abilities in relation to autistic and non-autistic others, and about autistic and non-autistic others' abilities to read their (the participant's) own minds. While autistic participants did report weaker mindreading abilities, this was only true in relation to non-autistic others. Both groups reported better mindreading abilities in same- than other-neurotype interactions, with autistic participants reporting mindreading abilities commensurate with non-autistic participants in relation to autistic targets. The same pattern was found when participants were asked about other people's mindreading abilities. The findings were more consistent with the DEP than deficit theories, as the target reference group strongly impacted participants' perceived mindreading abilities. While self-reported beliefs do not necessarily reflect actual mindreading abilities, they may still have important consequences for intergroup relations and social outcomes for autistic people.