Introduction: Mental health concerns have been noted to be highly prevalent for youth with intellectual disability (ID), with or without autism spectrum disorder (ASD). The purpose of the current study was to examine a Canadian sample of youth with ID, with or without ASD, to explore caregiver-reported percentages, predictors, and treatment methods for mental health concerns. Method: The sample included 358 caregivers who completed the GO4KIDDS survey on behalf of their child between the ages of 4 and 20 years (M = 11.36; SD = 3.82). Results: In total, 56% of youth with ID (with or without ASD) were reported to experience mental health concerns. Adaptive functioning and diagnosis were significant predictors of mental health concerns. Of the youth who were reported to experience mental health concerns, 80% received some type of treatment, most commonly informal therapies (52%). Conclusion: More than half of the samples were reported to experience mental health concerns and while the majority received some type of treatment, many of the treatments utilized are not evidence-based.