Objective: To explore how caregivers are involved in making treatment decisions for older people living with dementia and a new diagnosis of cancer. Method: A systematic review of PubMed, CINAHL, PsycINFO, Web of Science, and Scopus databases was conducted. Studies recruiting formal or informal caregivers for older people with dementia and a diagnosis of cancer were considered for inclusion. Results: Of 1761 articles screened, 36 full texts were assessed for eligibility, and six were included in the review.