This systematic review summarizes the major developments in extracorporeal membrane oxygenation (ECMO) circuitry in pediatrics over the past 20 years and demonstrates the impacts of those developments on clinical outcomes. This systematic review followed structured Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A total of 1987 studies were retrieved, of which 82 were included in the final analysis. Over the past 20 years, ECMO pumps have shifted from roller pumps to centrifugal pumps. Silicone and polypropylene hollow fiber membrane oxygenators were initially used but have been replaced by polymethylpentene hollow fiber membrane oxygenators, with other ECMO components poorly reported. Considerable variability in mortality was found across studies and there was no statistical difference in mortality rates across different periods. The duration of ECMO and other outcome measures were inconsistently reported across studies. This systematic review demonstrated technological developments in pumps and oxygenators over the last two decades, although patient mortality rates remained unchanged. This could be because of ECMO support applied to patients in more critical conditions over the years. We also highlighted the limitations of methodology information disclosure and outcome measures in current ECMO studies, showing the need of reporting standardization for future ECMO studies.