Background: Platelet counts (PLT) of less than 100 x 10⁹/L are diagnostic of immune thrombocytopenia (ITP), a kind of acquired thrombocytopenia. High rates of destruction of platelets and decreased platelet synthesis are the root causes of thrombocytopenia among cases with primary immune thrombocytopenia. ITP cannot be definitively diagnosed; consequently, primary ITP is still a diagnosis of exclusion made after all other possible etiologies of thrombocytopenia have been ruled out. Multiple studies have found elevated mean platelet volume (MPV) levels in patients with ITP, raising the prospect of using MPV as a diagnostic and prognostic marker for the disease. However, there has not been sufficient research into the clinical significance of MPV in children with ITP. Objective: This review article aimed to assess the rolemean platelet volume in the diagnosis and prognosis of ITP. Methods: Mean platelet volume, pediatrics, and idiopathic thrombocytopenia were all looked for in PubMed, Google scholar, and Science direct. References from relevant literature were also evaluated by the authors, but only the most recent or complete studies from January 2000 to May 2021 were included. Due to the lack of sources for translation, documents in languages other than English have been ruled out. Papers that did not fall under the purview of major scientific investigations, such as unpublished manuscripts, oral presentations, conference abstracts, and dissertations, were omitted. Conclusion: It is possible to predict the course of ITP in children by monitoring changes in mean platelet volume (MPV) throughout time and the MPV at diagnosis.