Young people with poor mental health are more likely to have poor educational attainment, employment prospects and physical health, and mental health problems often persist into adulthood. Mental health promotion aims to elevate levels of mental wellbeing while protecting against its loss and reducing the prevalence of mental health problems. The delivery of and access to mental health promotion has evolved over recent years. This research explored the area of technology for promoting mental wellbeing in young people. The research was in two parts: focus groups with 34 young people aged 12–18 years, which identified a preference for digital sources of support; and a review of 14 apps and websites for supporting 12–18 year olds to promote their mental wellbeing, which identified significant shortfalls. The main contribution to HCI is new insights and opportunities for design to support young people aged 12–18 years to promote their mental wellbeing.