Results from cognitive neuroscience have been cited as evidence in courtrooms around the world, and their admissibility has been a challenge for the legal system. Unfortunately, the recent reproducibility crisis in cognitive neuroscience, showing that the published studies in cognitive neuroscience may not be as trustworthy as expected, has made the situation worse. Here we analysed how the irreproducible results in cognitive neuroscience literature could compromise the standards for admissibility of scientific evidence, and pointed out how the open science movement may help to alleviate these problems. We conclude that open science not only benefits the scientific community but also the legal system, and society in a broad sense. Therefore, we suggest both scientists and practitioners follow open science recommendations and uphold the best available standards in order to serve as good gatekeepers in their own fields. Moreover, scientists and practitioners should collaborate closely to maintain an effective functioning of the entire gatekeeping system of the law.