Lesbian women and gay men are at greater risk of post-traumatic stress disorder (PTSD) than heterosexual people, however few studies have examined PTSD in older lesbian women and gay men. This study examined predictors of having ever been diagnosed with PTSD, as well as relationships to current quality of life, among 756 lesbian women and gay men aged 60 years and older in Australia. Participants were surveyed on their sociodemographic characteristics, experiences of sexual orientation discrimination over their lifetime, whether they had ever been diagnosed with PTSD, whether they were currently receiving treatment for PTSD, and their current quality of life. After adjusting for sociodemographic variables, participants who reported having a PTSD diagnosis (11.2%) had significantly more frequent experiences of discrimination over their lifetime and were significantly less likely to currently be in a relationship. Older lesbian women were significantly more likely than older gay men to report ever having had a PTSD diagnosis. Additionally, having ever been diagnosed with PTSD significantly predicted current poorer quality of life. These findings suggest that a history of PTSD among older lesbian women and gay men is linked to experiences of discrimination and other factors, with associated links to current quality of life.