Tumor has been considered as a serious public health concern and a prominent contributing factor to the prevalence of cancer and global mortality rates. Extensive epidemiological investigations have consistently established a correlation between a high consumption of fungal polysaccharides-rich foods, and a decreased risk of tumorigenesis. Although numerous studies have exemplified the anti-tumor properties exhibited by fungal polysaccharides compounds, a comprehensive and systematic evaluation of their efficacy and mechanisms in treating tumors remains notably limited. This article reviews clinical trials and experimental studies regarding the anti-tumor effects and respective molecular mechanisms of common dietary fungal polysaccharides from 2011 to 2023 available in PubMed. Based on published investigations, dietary fungal polysaccharides exhibit various mechanisms of action that contribute to their anti-tumor potentials, including the effects of antioxidation, anti-angiogenesis, apoptosis induction, cell cycle regulation and immunomodulation. This comprehensive review also highlights recent advancements in understanding the bioavailability of fungal polysaccharides, as well as the essential role played by gut microbes in their metabolism. However, further research is needed to enhance our understanding of the intricate mechanisms underlying fungal polysaccharides' bioavailability. Such studies will undoubtedly facilitate the development of precise dietary interventions for preventing and treating tumors. •This article reviews the antitumor effects and mechanisms of polysaccharides in fungi.•High consumption of polysaccharides in fungi decreases risk of tumor.•Gut microbes closely related to polysaccharides in fungi.