Background: This mixed-methods study was designed to explore young Australian men's attitudes and behaviour in relation to mental health and technology use to inform the development of online mental health services for young men.Methods: National online survey of 486 males (aged 16 to 24) and 17 focus groups involving 118 males (aged 16 to 24).Results: Young men are heavy users of technology, particularly when it comes to entertainment and connecting with friends, but they are also using technology for finding information and support. The focus group data suggested that young men would be less likely to seek professional help for themselves, citing a preference for self-help and action-oriented strategies instead. Most survey participants reported that they have sought help for a problem online and were satisfied with the help they received. Focus group participants identified potential strategies for how technology could be used to overcome the barriers to help-seeking for young men.Conclusions: The key challenge for online mental health services is to design interventions specifically for young men that are action-based, focus on shifting behaviour and stigma, and are not simply about increasing mental health knowledge. Furthermore, such interventions should be user-driven, informed by young men's views and everyday technology practices, and leverage the influence of peers.