The prevalence of mental health problems in people with intellectual disability is higher than people in general. Depression and anxiety are common mental disorders that people with intellectual disability experience in their lives. Since the youth age range is a transition from childhood to adulthood, it is important to address the mental health problems, specifically depression, amongst youth with intellectual disability. Cognitive behavioral therapy is a promising treatment for depression among this population, while due to the low cognitive ability of youth with intellectual disability, adaptation to this therapy is needed. This study aims to investigate adaptations to cognitive behavior therapy and outcome measurement instruments among young adults aged between 15 and 24 with ID who have symptoms of depression. To address the study's aim, a systematic search was conducted across four electronic databases: MEDLINE, CINAHL, PsycINFO, and Scopus, resulting in the selection of eight articles. The inclusion criteria were selected based on the PIO framework. The result demonstrated that three CBT adaptations, including simplification, language, and developmental level, were the most frequent. Also, similar adaptations were made to self-report outcomes measurement tools under the categories of adaptations to content and administration procedure. The study concluded that to effectively advocate for the voice of youth with intellectual disabilities (ID), it is essential to address countertransference and rehabilitation approaches within the adaptations category. Additionally, to have a comprehensive assessment of mental health problems, there is a need for the adaptation of self-report measurement instruments.