Objective The objective of the review was to identify, critically appraise and synthesize evidence on the impact of professional interpreters on outcomes for hospitalized children from migrant and refugee families with limited English proficiency. Introduction A key strategy to facilitate effective communication between limited-English-proficient migrant and refugee families and healthcare providers is the use of professional interpreters. Despite awareness of the importance of professional interpreters, interpreters are underutilized. This results in suboptimal care, including poor access to health care, increased risk of serious medical events, increased admission to hospital and inadequate health literacy. Inclusion criteria Limited-English-proficient migrant, refugee or asylum-seeker families with a hospitalized child aged 0 to 18 years, who had used a professional interpreter, were considered for this review. Comparators included standard care or no interpreter, and reported results of comparisons of the duration, frequency or mode of interpreter delivery. Outcomes were length of stay in hospital, unplanned readmission rates to hospital, non-attendance at hospital clinic appointments and ambulatory care, child and/or parent satisfaction with care in hospital, adherence to treatment, medication errors, and other adverse events relating to patient safety. The review considered all studies conducted using a quantitative approach. Methods A three-step search strategy was used. Databases were searched in December 2018 for published and unpublished articles. Studies published in English were considered for inclusion. The recommended JBI approach to critical appraisal, study selection, data extraction and data synthesis was used. Results Six articles reporting results from three randomized controlled trials and one observational study were included. Studies were undertaken in the United States involving Spanish-speaking participants. Three studies were in emergency departments. There was a total of 1813 fa...