Neuromyths are commonly held misconceptions about the brain believed by both the general public and educators. While much research has investigated the prevalence of myths about the typically developing brain, less attention has been devoted to the pervasiveness of neuromyths about neurodevelopmental disorders, which have the potential to exacerbate stigma. This preregistered study investigated to what extent neuromyths about neurodevelopmental disorders (namely dyslexia, attention deficit hyperactivity disorder, autism spectrum disorders, and syndrome) are endorsed by two groups: the general public and those working in education. In an online survey, 366 members of the general public and 203 individuals working in education rated similar numbers of myths to be true, but more about neurodevelopmental disorders than general neuromyths. As the frequency of access to brain information emerged as a protective factor against endorsing myths in both populations, we argue that this problem may be addressed via provision of neuroeducational resources.