It has been revealed that patients suffering from chronic inflammatory disorders have a much higher risk of malignancy in the affected organs. CD4+ T cells are essential for the initiation and continuation of adaptive immunity. Their role in antitumor immunity is multifaceted, reflecting the numerous effects of different kinds of them. Although Th1 and Th2 were the only subsets of CD4+ T helper at first, other subtypes, including Th17 and Treg cells, have been defined in the last decades. Th17 cells are distinguished from Th1 and Th2 by high-level IL-17 production. Th17 cells also produce other cytokines such as IL-6, IL-21, IL-22, IL-23, GM-CSF, and TNF-α. There is evidence of both antitumor and protumor activities of Th17 cells and IL-17. Thus, it seems that the dual roles of the Th17 cell are environment-dependent, and the environmental factors determine its antitumor or protumor function. While most of the studies indicate the antitumor role of IL-23, significant evidence implies the protumor role of IL-22. Future studies should be conducted to identify the exact role of Th 17 cell and its secreted cytokines.