The Internet has been argued to provide diverse sites for health communication and promotion, including issues that constitute major public health priorities such as the prevention of dementia. In this study, discursive psychology is used to examine how information about dementia risk prevention was presented on the websites of the most prominent English-language, nonprofit dementia organizations. We demonstrate how information about dementia risk and its prevention positions audiences as at-risk of developing dementia and constructs preventive behavior as a matter of individual responsibility. Websites represented participation in certain lifestyle practices as normative and emphasized audience members’ personal responsibility for managing dementia risk. It is argued that such representations promote a moral identity in regard to brain health in which an ethic of self-responsibility is central. The implications of such identity construction in a context of increasing prevalence of dementia diagnosis are discussed.