Acceptance and Commitment Therapy (ACT) has emerged over the last twenty years within the context of the Third Wave of Cognitive Therapies, and has been utilised with reported success in a range of therapeutic and mental health settings. Social and self-stigma related to seeking assistance for mental health and other concerns has been shown to reduce client engagement with therapeutic support. Numerous studies have been undertaken that support ACT as an empirically validated framework for engaging stigmatised client groups. This paper provides a review of the key philosophical underpinnings and prominent techniques employed in ACT. Further, the paper highlights the utility of ACT in treating mental illness and other conditions by encouraging therapeutic participation through a use of techniques that inherently reduce the self and social stigma related to psychological disturbance and disability.