Context Advance care planning (ACP) is defined as a person-centered, ongoing process of communication that facilitates patients' understanding, reflection, and discussion of goals, values, and preferences for future care. There is evidence for the general palliative care population that ACP increases compliance with patients' end-of-life preferences and improves quality of care near the end of life. Objectives To gain insight into what is known about the use and effects of ACP in palliative care for people with intellectual disabilities (IDs). Methods Four databases were searched systematically: PubMed, PsycINFO, Embase, and CINAHL. A stepwise procedure was used to identify relevant studies based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement. The review included empirical quantitative, qualitative, and mixed methods studies concerning people with ID who receive palliative care or who died non-acutely, and describing ACP. Methodological quality was graded using a critical appraisal tool. Results A total of 14 studies were included. Most studies examined the perspective of professionals and/or relatives. None of the studies focused on the perspective of patients with ID. The studies concerned different elements of ACP, mainly decision-making and organizational policies. No effect studies were found. Obstructing factors were difficulties in recognizing palliative needs and uncertainties among relatives and professionals about their roles and tasks in ACP. Conducive factors were good working relationships between professionals and relatives. Conclusion There are some indications that ACP could be useful for people with ID, but more knowledge is needed about whether and how ACP should be used.