BackgroundTo undertake a systematic review of studies describing the proportion of children admitted to a paediatric intensive care unit (PICU) for respiratory syncytial virus (RSV) and/or bronchiolitis who were born preterm, and compare their outcomes in PICU with children born at term.MethodsWe searched Medline, Embase and Scopus. Citations and references of included articles were searched.We included studies published from the year 2000 onwards, from high-income countries, that examined children 0–18 years of age, admitted to PICU from the year 2000 onwards for RSV and/or bronchiolitis.The primary outcome was the percentage of PICU admissions born preterm, and secondary outcomes were observed relative risks of invasive mechanical ventilation and mortality within PICU.We used the Joanna Briggs Institute Checklist for Analytical Cross-Sectional Studies to assess risk of bias.ResultsWe included 31 studies, from 16 countries, including a total of 18,331 children.Following meta-analysis, the pooled estimate for percentage of PICU admissions for RSV/bronchiolitis who were born preterm was 31% (95% confidence interval: 27% to 35%). Children born preterm had a greater risk of requiring invasive ventilation compared to children born at term (relative risk 1.57, 95% confidence interval 1.25 to 1.97, I2= 38%). However, we did not observe a significant increase in the relative risk for mortality within PICU for preterm-born children (relative risk 1.10, 95% confidence interval: 0.70 to 1.72, I2= 0%), although the mortality rate was low across both groups.The majority of studies (n= 26, 84%) were at high risk of bias.ConclusionsAmong PICU admissions for bronchiolitis, preterm-born children are over-represented compared with the preterm birth rate (preterm birth rate 4.4% to 14.4% across countries included in review). Preterm-born children are at higher risk of mechanical ventilation compared to those born at term.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12887-023-04150-7.