Autistic adults have high rates of co-occurring mental health conditions, like anxiety and depression and co-occurring sleep issues, like insomnia. There is a critical need to develop empirically supported psychological interventions that address co-occurring mental health conditions. However, there is little limited published data concerning psychological interventions for autistic adults. To conduct rigorous evaluation of psychological interventions for autistic adults, we need to be able to reliably measure clinical symptoms and track change over time. Sleep issues and psychological flexibility are thought to be key transdiagnostic processes underlying poor mental health in non-autistic adults. However, there is no published work examining the validity of measures of sleep issues or psychological flexibility in autistic adults. Questionnaires that measure these constructs and which are valid for autistic adults are needed. This study aims to validate various measures of sleep issues and psychological flexibility that are commonly used with the general population for use with autistic adults. In collaboration with researchers at LaTrobe University and Brigham Young University, we have developed an online survey of these measures to distribute to American and Australian autistic and non-autistic adults.