Objective: Adverse childhood experiences (ACEs) are early life experiences that influence mental health outcomes, though there are mixed findings reported in relation to attention deficit hyperactivity disorder (ADHD) symptoms. The current study compared adults who experienced ACEs on measures of ADHD symptom reporting, psychological symptoms, and neurocognitive test performance. Method: The sample (n = 115) had mean age of 28.42 (SD = 6.46); educational attainment of 16.47 years (SD = 1.99); and was 35% male/65% female and racially/ethnically diverse. Participants completed measures of ACEs, ADHD symptoms, psychopathology, and perceived stress, as well as neuropsychological tests. Results: The high ACEs group endorsed higher levels of childhood/adulthood inattentive, impulsive, and hyperactive symptoms, and overall childhood symptoms when compared to the low ACEs group. Conclusions: This study provides a more comprehensive understanding of the association between ACEs and cognitive/mental health outcomes. Greater ACEs resulted in higher ADHD symptom reporting but not significantly greater psychological symptoms or worse neurocognitive performance.