TCF7L2 also known as TCF4 is a high mobility group (HMG) box-containing transcription factor that plays a key role in the Wnt signaling pathway. TCF7L2 is primarily located in the cytoplasm, where TCF7L2 forms a complex with β-catenin before translocating to the nucleus to regulate the expression of Wnt target genes, many of which are associated with cancer. The interaction between TCF7L2 and β-catenin is essential for the activation of these genes, and the phosphorylation of TCF7L2 can influence TCF7L2′s interaction with other proteins, such as c-Jun, which is involved in the regulation of intestinal tumorigenesis. TCF7L2′s importance extends beyond cancer, as TCF7L2 has also been implicated in neuropsychiatric disorders, including bipolar affective disorder, highlighting TCF7L2′s significance in both developmental and pathological processes.