Individuals with intellectual disability (ID) and traumatic brain injury experience mental health issues at a higher rate than the general population. They are typically more vulnerable to stress, have fewer coping skills, and possess a smaller system of natural supports. It is clear that level of intelligence is not the sole indicator of the appropriateness of psychotherapy and that the full range of mental health services are able to help improve the quality of life for patients with intellectual disability. Special issues related to motivational interviewing, cognitive behavioral therapy (CBT), and supportive psychotherapy are described with specific attention to special issues for the intellectual disability population and effective adaptations addressed.