Wilms tumor (WT) is the most common renal malignant tumor in children. The traditional clinical hierarchical diagnosis and treatment scheme cannot achieve the clinical goal of guiding precise risk stratification, especially in patients without high-risk factors. For example, patients with the same clinical phenotype and receiving the same treatment may have significant differences in prognosis, indicating that the disease is much more complex than previously recognized. This individual heterogeneity requires more in-depth molecular phenotypic studies to determine new markers and targets. Circular RNA (circRNA) is a newly discovered non-coding RNA. A large number of studies have reported that dysregulated circRNA mainly plays the role of miRNA sponges to regulate multiple phenotypes of cancer cells, including proliferation, invasion, migration, cycle arrest, and chemotherapy resistance. This molecule may also become a promising marker and target for cancer diagnosis and treatment. Compared with adult cancers, the study of circRNA in WT is still in its infancy. Based on the existing literature, this paper systematically reviewed the latest progress in the expression pattern, biological function, and clinical value of circRNA in WT, and discussed the limitations of current research and future directions.