Emerging evidence suggests that emotion regulation (ER) impairment in those with ASD is associated with poor mental health. This study used the Emotion Dysregulation Inventory, a new norm-referenced ER measure with clinical cut-offs, developed and validated in ASD and non-ASD samples, to establish rates of ER impairment and understand its association with psychiatric service use in ASD. Parents of 6-17 year olds in three well-characterized samples (nationally representative US n = 1,000; community ASD n = 1,169; inpatient ASD n = 567) completed a battery of questionnaires about their child. The prevalence of ER impairment was significantly higher in the ASD groups compared to the nationally representative sample and highest in the psychiatric Inpatient ASD group. The community ASD and inpatient ASD samples were four and seven times more likely, respectively, to exceed clinical cutoffs for emotional reactivity than the general US sample. Similarly, history of psychiatric hospitalization, recent emergency services use (police contact, emergency room visits, or in-home crisis evaluations for emotional or behavioral concerns in the past 2 months), and psychotropic medication prescriptions were significantly higher in the ASD groups. ER impairment was significantly associated with all forms of psychiatric service use, after controlling for demographics (age, sex, race), co-occurring intellectual disability, and ADHD symptoms. This is the first large-scale study to document substantially higher rates of ER impairment in youth with ASD compared to the general population. The importance of ER impairment is underscored by its association with higher utilization of inpatient, emergency, and medication services in ASD, after accounting for demographics and ADHD-related symptoms. Lay Summary This study compared problems with emotion regulation in large samples of youth with and without ASD. An ASD community sample had two to four times more youth with clinically elevated regulation impairments compared to youth without ASD. Emotion regulation impairment was also related to using psychiatric hospitalizations, emergency services, and medications in the ASD group. This study suggests that screening for emotion regulation difficulties in ASD is important and treatment may have a wide ranging impact.