‘Mental health action’ is action that individuals or groups take to benefit their own mental health or that of others. This talk will describe the development and evaluation of three interventions to promote mental health action using the internet. The first is Partners in Parenting, which teaches parents of adolescents what they can do to prevent anxiety problems and depression in their children. The second is Mood Memos, which promotes self-help strategies for prevention of depression adults with mild symptoms. The third is Mental Health First Aid training by e-learning, which has been used to promote better support to people with mental health problems in workplaces and for medical and nursing students to better support their peers. It is concluded that societies need to promote mental health action by all sections of the community if they are to succeed in reducing the prevalence of mental disorders.