Abstract Background Unplanned hospital readmission (UHR) after paediatric neurosurgery is an important indicator of surgical outcomes. As this field deals with complex cases, there is an increased likelihood of potential complications and the subsequent need for readmission. Hence, the study aims to identify factors contributing to 30-day and 90-day UHR rates in children undergoing neurosurgical procedures. Methods A systematic review (Prospero CRD 42023455779) was conducted, which included studies from Embase, Medline, CINAHL, and Global Index Medicus databases that reported unplanned readmissions within 30-/90-days of an index neurosurgical procedure. Quality and risk of bias assessment was done using the Newcastle-Ottawa scale. Data extraction and narrative synthesis were performed to identify significant factors associated with UHR. Results 2593 titles were identified following the search strategy. 52 studies were included after screening and quality appraisal. Most studies were from the United States and are retrospective cohort in nature. Majority were cranial procedures (n = 30), with common ones being shunt procedures for hydrocephalus and cranial tumour resections. Aetiology-related, procedural complexities, and age emerged as the three most common significant risk factors. Age is a significant predictor (9/52), with younger children facing higher odds compared to their older counterparts across different procedures. While early readmissions can be due to disease progression, some are linked to preventable causes. The included studies also exhibited significant heterogeneity. Variations in definitions and examined variables, as well as the inclusion of studies from both national databases and single institutions, contributed to this heterogeneity. Conclusions Overall, findings from this study contribute to a collective understanding of factors affecting unplanned readmissions in paediatric neurosurgery. Key messages • Identified risk factors can help guide creating and refining surgical protocols for post-operative monitoring and follow-up. • UHRs reflect the interplay among surgical complexity, patient characteristics such as age, and disease aetiology.