Suicide is a leading cause of death among Aboriginal and Torres Strait Islander people. Friends, family and frontline workers (for example, teachers, youth workers) are often best positioned to provide initial assistance if someone is at risk of suicide. We developed culturally appropriate expert consensus guidelines on how to provide mental health first aid to Australian Aboriginal and Torres Strait Islander people experiencing suicidal thoughts or behaviour and used this as the basis for a 5-hour suicide gatekeeper training course called Talking About Suicide. This paper describes the outcomes for participants in an uncontrolled trial of this training course. We undertook an uncontrolled trial of the Talking About Suicide course, delivered by Aboriginal and Torres Strait Islander Mental Health First Aid instructors to 192 adult (i.e. 18 years of age or older) Aboriginal and Torres Strait Islander (n = 110) and non-Indigenous (n = 82) participants. Questionnaires capturing self-report outcomes were self-administered immediately before (n = 192) and after attending the training course (n = 188), and at four-months follow-up (n = 98). Outcome measures were beliefs about suicide, stigmatising attitudes, confidence in ability to assist, and intended and actual actions to assist a suicidal person. Despite a high level of suicide literacy among participants at pre-course measurement, improvements at post-course were observed in beliefs about suicide, stigmatising attitudes, confidence in ability to assist and intended assisting actions. While attrition at follow-up decreased statistical power, some improvements in beliefs about suicide, stigmatising attitudes and intended assisting actions remained statistically significant at follow-up. Importantly, actual assisting actions taken showed dramatic improvements between pre-course and follow-up. Participants reported feeling more confident to assist a suicidal person after the course and this was maintained at follow-up. The course was judged to be culturally appropriate by those participants who identified as Aboriginal and/or Torres Strait Islanders. The results of this uncontrolled trial were encouraging, suggesting that the Talking About Suicide course was able to improve participants' knowledge, attitudes, and intended assisting actions as well as actual actions taken.