This chapter explores the under-recognized yet highly prevalent issue of cognitive impairment among people experiencing homelessness. It outlines the multifactorial causes of cognitive dysfunction—including traumatic brain injury, substance use, dementia, mental illness, and developmental disorders. The chapter highlights the significant consequences of cognitive deficits on functional abilities, engagement with health and social services, vulnerability to exploitation, and chronic homelessness. Assessment of cognitive impairment in this population is complicated by environmental instability, overlapping symptoms with psychiatric conditions and lack of specialized tools. However, it remains crucial for informed care planning and service delivery. Screening methods such as the Montreal Cognitive Assessment, WHODAS 2.0, and the Trail Making Tests are discussed, along with strategies for assessing decision-making capacity. The chapter stresses the importance of building therapeutic relationships and adapting communication approaches in care. It concludes with a call for multidisciplinary, trauma-informed interventions—including occupational therapy and cognitive remediation—that are tailored to the unique needs of cognitively impaired individuals.