Objective: Perioperative anxiety is described as an uncomfortable, tense or unpleasant mood at any point in the surgical journey. It can alter the way patients’ deal with the surgical experience and think about surgical treatments in the future. This systematic review aims to investigate the methods of diagnosing perioperative anxiety and assess the prevalence of the condition within the global paediatric population undergoing operations. Materials and methods: The systematic review was conducted in accordance with the PRISMA Checklist (a 27-item checklist to address introduction, methods, results and discussion with a systematic review). Medline and Scopus databases were searched. Two independent reviewers determined which papers were suitable for inclusion. Inclusion was determined by the mention of prevalence of operative-related anxiety, in a population under 18 years old and patients that were undergoing an operation in a hospital setting. Initially, 48 papers were found and, after screening, a total of 12 eligible studies were included. Data was extracted on the method of diagnosis of anxiety, the prevalence of perioperative anxiety, the time of assessment and the age of the cohort. Cochrane bias assessment was used to assess the presence of types of bias in randomised control trials (RCTs) included and the risk of bias in non-randomised studies of interventions tool in each non-RCTs. Results: 83% (n=10) studies used the modified Yale Preoperative Anxiety Scale (mYPAS) for diagnosis. The overall average prevalence of perioperative anxiety in each paediatric cohort undergoing surgery was 42.1% (95% CI 30.5 - 53.7). There was not sufficient evidence to support a relationship between the age of the patient groups, the time of the anxiety assessment and the prevalence of the perioperative anxiety. Conclusion: Paediatric anxiety remains a significant factor affecting over a third of all children who undergo operations. The vast majority of papers used the mYPAS for diagnosis although there is still some debate about the most appropriate diagnostic tool. Further studies are needed to assess the factors influencing perioperative anxiety and to evaluate the impact of perioperative anxiety on the patient experience and recovery.