Abstract: As the most important transcription factor in regulatory T cells, forkheadbox protein 3 (FOXP3) has been extensively investigated in T cells. However, FOXP3, a tumor type-dependent transcription factor, is expressed at different levels in different tumors. In some tumors, FOXP3, as a suppressor, inhibits proliferation and metastasis. In other tumors, FOXP3, as an oncogene, mediates tumor immune escape. In this review, we summarize the expression levels and functions of FOXP3 in different tumor types to provide evidence for further research.