emerging adulthood (ea; ages 18-29) is a unique developmental period when individuals transition from their teenage years into adulthood, experiencing increased demands associated with independence. for some, there are increased levels of uncertainty and mental health difficulties, but, for those who adapt to such transitions, there are positive implications in later life. adverse childhood experiences (aces) may potentiate transitional difficulties in ea. aces are known to disrupt neurodevelopment and executive function (ef), a key set of mental skills that include emotion regulation and planning. as such, emerging adults who experience aces may be at an increased risk for impairment during these important transitional years. this study examines whether aces are related to decreases in ef and functional impairment in emerging adults. specifically, hayes’ process macro is used to test whether the relationship between aces and functional impairment was moderated by ef. a total of 162 emerging adults completed an online self-report questionnaire package assessing aces, ef, and functional impairment. as expected, regression analyses highlighted that number of endorsed aces significantly predict self-reported ef scores in emerging adults. similarly, aces predict self-reported functional impairment in the domains of school, family, life skills, risky behaviours, self-concept and social relationships. however, ef did not significantly moderate the relationship between aces and functional impairment, contrary to expectation. upon further investigation, exploratory mediational analyses demonstrated that ef significantly mediates the relationship between aces and functional impairment such that ef partially explains the relationship between aces and functional impairment in emerging adults. the present results demonstrate the need to consider ef as a target to reduce functional impairment in emerging adults.