Young adults with intellectual and developmental disabilities (IDDs) are at an increased risk of developing mental health disorders. Mindfulness may be one strategy that can help support the mental health needs of this particular population; however, those with (IDDs) may need additional support in cultivating the practice. The purpose of this study was to investigate the use of a wearable device designed to provide neurofeedback to help promote state mindfulness in young adults with (IDDs). Additionally, attention and affect mechanisms were examined, as well as the social validity of using the wearable device. Using an A-B-A-B single-subject study design, five ("age range" = 18-25) students completed 20 sessions that consisted of listening and not listening to neurofeedback. Results provide some support for the positive effect of neurofeedback on state mindfulness, paying attention to the breath, and positive affect. All five students reported acceptability of using the device.