Triboelectric nanogenerators (TENGs) are eco-friendly energy-harvesting systems that produce electrical energy from disordered mechanical energy. To enhance the triboelectric performances of TENGs, many researchers have conducted in-depth studies of the polymer materials utilized in TENGs, so numerous studies have been reported on the relationship between their material properties and their energy-harvesting capabilities. Triboelectric performance depends on the electrical properties of the materials used, such as their electron affinities and dielectric constants. Representative examples of positive and negative tribomaterials include PA6, PEO, PVDF, and fluorinated sulfur copolymers, respectively. This article introduces the relationship among the compositions, structures, triboelectric performances of the polymer materials, and composites used in TENGs and summarizes the representative polymer materials applied in the latest TENGs.