Children’s ability to accurately monitor their performance is crucial for self-regulated learning and academic achievement, but interventions are rare. We evaluated a six-time computerized training to improve young primary school children’s uncertainty monitoring with feedback. We assigned the participants (N = 182; M = 7.47 years) either to a metacognitive group, a performance group, or an active control group. Pre and post training, all participants received a baseline recognition memory assessment and provided confidence judgments on each recognition. During training, children in the metacognitive condition received feedback on their memory accuracy and the correspondence between their memory accuracy and their confidence judgments. Children in the performance condition received solely feedback on their memory accuracy. Children in the active control group solved attention control tasks. Other than expected, results revealed that metacognitive and performance feedback did not improve children’s uncertainty monitoring. Important implications for future intervention studies are discussed.