Despite very high rates of suicidal thoughts and behaviors (STB) in autistic adults, the key psychosocial drivers of this phenomenon remain unknown. To investigate, we examined how lifetime stressor exposure and severity, which have been found to predict STB in non-autistic populations, related to STB in a multinational dataset of 226 autistic adults from the United Kingdom and Australia (67% female; M[subscript age] = 41.8, SD = 13.6, range = 19-73 years old). Results revealed that autistic men and women differ with respect to the count, severity, and type of stressors they experienced over the life course. Whereas autistic men were exposed to more numerous legal/crime-related stressors, autistic women experienced more stressors related to social relationships and chronic humiliation and typically experienced stressors as more severe. In addition, whereas chronic interpersonal loss was related to STB for men, acute stressors involving physical danger and lower exposure to chronic entrapment were related to STB in autistic women. These findings indicate that certain lifetime stressors may be differentially experienced, and relevant to STB, in autistic men versus women. They also suggest that screening for lifetime stressor exposure may help identify autistic individuals at greatest risk of suicide.