Men are more likely to take their own lives, but less likely to seek professional help when they are depressed, especially as they age. Important determinants of help-seeking are perceived public and self-stigma concerning depression and suicide. Yet little research has explored sex and age differences in public stigma of men’s depression and suicide, and in self-stigma of depression. Our study examined this neglected topic with a nationally representative survey of 452 male and 449 female (N = 901) Canadian adults ranging in age from 18—83. We examined age (18—34; 35—49; 50—64; 65+) and sex differences in public stigma of men’s depression, public stigma of men’s suicide, and self-stigma. Results demonstrated that, as expected, men were more likely to endorse most aspects of public stigma of men’s depression and suicide. Our data also showed that public stigma was highest in younger adults, with young men demonstrating especially high levels. Our hypotheses that self-stigma would be largely independent of sex, and higher in younger adults, were also confirmed. In conclusion, although young men endorsed the highest levels of public stigma, overall levels of public stigma were low. This suggests that antistigma efforts to increase the use of mental health services might be most effective with a focus on self-stigma in young men and women. (PsycINFO Database Record (c) 2019 APA, all rights reserved)