This study investigated the effect of feedback on the accuracy (realism) of 12-year-old children's metacognitive judgments of their answers to questions about a film clip. Two types of judgments were investigated: confidence judgments (on each question) and frequency judgments (i.e. estimates of overall accuracy). The source of feedback, whether it was presented as provided by a teacher or a peer child, did not influence metacognitive accuracy. Four types of feedback were given depending on whether the participant's answer was correct and depending on whether the feedback confirmed or disconfirmed the child's answer. The children showed large overconfidence when they received confirmatory feedback but much less so when they received disconfirmatory feedback. The children gave frequency judgments implying that they had more correct answers than they actually had. No main gender differences were found for any of the measures. The results indicate a high degree of malleability in children's metacognitive judgments.