The use of digital technologies in the management of mental illness, and more generally in the promotion of well-being and mental health, has received much recent attention and is a focus of current health policy. We conducted a narrative review to explore the opportunities and risks of digital technologies in mental healthcare specifically for people with intellectual disability, a sometimes marginalised and socially excluded group. The scope of digital mental health is vast and the promise of cheaper and more effective interventions delivered digitally is attractive. People with intellectual disability experience high rates of mental illness and could benefit from the development of novel therapies, yet seem to have been relatively neglected in the discourse around digital mental health and are often excluded from the development and implementation of new interventions. People with intellectual disability encounter several barriers to fully embracing digital technology, which may be overcome with appropriate support and adaptations. A small, but growing, literature attests to the value of incorporating digital technologies into the lives of people with intellectual disability, not only for promoting health but also for enhancing educational, vocational and leisure opportunities. Clearly further evidence is needed to establish the safety and clinical efficacy of digital mental health interventions for people with and without intellectual disability. A digital inclusion strategy that explicitly addresses the needs of people with intellectual disability would ensure that all can share the benefits of the digital world.