This paper describes the development of culturally appropriate guidelines for providing first aid to an Australian Aboriginal or Torres Strait Islander experiencing a mental health crisis or developing a mental illness. A panel of Aboriginal mental health experts participated in six independent Delphi studies investigating depression, psychosis, suicidal thoughts and behaviours, deliberate selfinjury, trauma and loss, and cultural considerations. The panellists reached consensus about culturally appropriate first aid for mental illness. A total of 536 statements about first aid actions were accepted for inclusion in a guideline (94 for depression, 151 for psychosis, 52 for suicidal thoughts and behaviours, 53 for deliberate self-injury, 155 for trauma and loss, and 31 for cultural considerations). The panellists affirmed the methodology and the guidelines themselves as useful and appropriate.