We predicted that mentalizing relates to social aspects of insight in psychosis. Thirty participants experiencing psychosis and presenting poor to moderate insight undertook a false belief picture sequencing task with control sequences. We used an improved scoring system that accounted simultaneously for speed and accuracy of mentalizing. While mentalizing was not significantly related to global insight, “awareness of psychosis”, “re‐labelling symptoms as abnormal”, or “understanding need for treatment”, it was positively related to the influence of the opinions of unspecified “others” on insight. Participants were insightful in predicting their doctor’s opinion, but this was unrelated to mentalizing. Intact social knowledge about doctors, rather than mentalizing, may be used to understand the doctor’s opinion. However, mentalizing is needed to incorporate others’ opinions about psychosis into one’s own insight, as the perspectives of unspecified “others” would likely vary more than that of medical professionals. The results suggest that medical professionals should be careful to distinguish simple recognition of their views from genuine insight.