The misinformation effect occurs when an eyewitness includes information in their account that is incongruent with the event they witnessed, and stems from being exposed to incorrect external sources. Yet little research has been undertaken on techniques that could protect eyewitnesses from the influence of misinformation, despite the dangerous consequences of distorted testimony. In this article, a method of enhancing self-confidence, called reinforced self-affirmation (RSA), was proven to reduce the misinformation effect in five experiments. First, participants watched or heard an original event take place. They were then exposed to post-event material containing false information about that event, and finally they were given a memory test about the original material. The RSA, which took place either before the post-event material or before the final test, consisted of self-affirmation (recalling the greatest achievements in life) and external positive feedback (simulated good' results in a memory test or fake favourable results on personality tests). A meta-analysis of all five experiments revealed that the overall effect of RSA on reducing the misinformation was significant (effect size of 0.94), suggesting that this technique has the potential to be developed for practical use to make eyewitnesses less vulnerable to misinformation.