Purpose <p>Lymphoma is a significant pediatric cancer, following acute leukemia and malignant brain tumors. Traditional diagnostic and staging methods, such as biopsies and the Ann Arbor system, may have limitations in accuracy and invasiveness. This systematic review aims to critically evaluate the utility of fluorine-18 fluorodeoxyglucose-positron emission tomography ([¹⁸F]FDG-PET), positron emission tomography/computed tomography (PET/CT), and positron emission tomography/magnetic resonance imaging (PET/MRI) in improving non-invasive staging, treatment response evaluation, and prognostic values in pediatric lymphoma.</p> Method <p>A systematic search of <i>PubMed</i>, <i>Scopus</i>, and <i>Web of Science</i> was conducted (2011–2024) using keywords related to pediatric lymphoma and PET. Data were extracted on study design, demographics, imaging protocols, tracer dosing, and quantitative PET parameters.</p> Results <p>Thirty-one studies met the eligibility criteria. Quantitative analysis primarily relied on the standardized uptake value (SUV), with additional use of metabolic tumor volume and total lesion glycolysis. Across diagnostic, staging, and follow-up phases, [¹⁸F]FDG-PET (alone or combined with CT/MRI) consistently showed higher sensitivity and the negative predictive value (NPV) (&gt;70%) than conventional imaging, though the positive predictive value remained moderate (&lt;50%). PET/CT provided more reliable prognostic value than PET alone or MRI. At follow-up, PET/MRI demonstrated better positive predictive value (PPV) than conventional imaging, which showed limited utility.</p> Conclusion <p>[¹⁸F]FDG-PET combined with CT or MRI enhances diagnostic accuracy and staging of pediatric lymphoma by improving the detection of nodal and extranodal disease. PET’s ability to reveal early metabolic changes supports timely assessment of treatment response and may reduce the need for invasive bone marrow biopsies. Nonetheless, concerns about radiation exposure, limited MRI coverage, and variable predictive value highlight the need for cautious application in children. Advanced parameters such as metabolic tumor volume and total lesion glycolysis offer additional prognostic potential, but further standardization and prospective validation are required. Overall, PET represents a promising, less invasive tool for staging and follow-up, with the potential to improve both diagnostic precision and patient outcomes.</p> Clinical trial number <p>Not applicable.</p> Graphical abstract <p></p>