Background Numbers of looked‐after children and young people (LACYP) in the UK have risen over the last seven years. Looked‐after children and young people should receive regular health assessments, including establishing immunization status and, if needed, developing a health plan to achieve full immunization. The Department for Education publish data on immunizations among LACYP to monitor both how well they are immunized and service performance. Methods A literature review was conducted using four databases (PubMed, Embase, Scopus and Web of Science) on immunization status of LACYP, factors affecting uptake and challenges to immunization, and interventions to improve immunization rates. Results Thirty‐two papers were identified, 16 of which were UK based. Looked‐after children and young people are less likely to be ‘up‐to‐date’ with their immunizations than children in the general population. Looked‐after children and young people are less likely to receive timely immunizations, and older LACYP are less likely to be ‘up‐to‐date’ than younger LACYP. Barriers to immunization include failure to attend health checks, absence from school and frequent placement moves. Unknown and discrepant immunization histories, name changes, sharing of information between organizations and obtaining consent for immunizations are also challenges. Conclusions In recent years, immunization of LACYP has been given a higher priority. However, the immunization figures produced by the Department for Education are problematic because of challenges in determining whether the child is ‘up‐to‐date’, and data are not comparable with the general population; ideally, this should be changed to correspond to routine immunization data. In the interim, for reporting purposes, the use of a tool to assist with determining a child's immunization status would be beneficial. When a child's immunization status is incomplete or unknown, Public Health England's algorithm for vaccination of individuals with uncertain or incomplete status should be used. Practice to improve immunization uptake amongst LACYP needs to be evaluated to develop evidence‐based recommendations.