Older men have the highest suicide rates worldwide, necessitating focused interventions (WHO, 2014). We have developed and are testing a 12-session community-based group intervention for men over 55 who are concerned, struggling, or worried about the transition to retirement. Meaning-Centered Men’s Groups (MCMG) draw on theory, research, and practice implicating existential considerations in contributing to or warding off thoughts of suicide (Heisel & Flett, 2016), and aim to build camaraderie through discussions about finding meaning in work, leisure, relationships, and generativity. We now present analyses investigating personality moderators of treatment outcomes in our trial of MCMG. Conscientiousness appears to significantly moderate the reduction in suicide ideation, and is negatively associated with Neuroticism and depression and positively associated with psychological well-being and life satisfaction. Findings will be discussed with reference to theory and research on personality, masculinity, and suicide prevention, and implications for mental health outreach to older men.