Two-dimensional (2D) semiconductors offer a promising prospect for high-performance and energy-efficient devices especially in the sub-10 nm regime. Inspired by the successful fabrication of 2D \(\beta\)-TeO\(_2\) and the high on/off ratio and high air-stability of fabricated field effect transistors (FETs) [Nat. Electron. 2021, 4, 277], we provide a comprehensive investigation of the electronic structure of monolayer \(\beta\)-TeO\(_2\) and the device performance of sub-10 nm metal oxide semiconductors FETs (MOSFETs) based on this material. The anisotropic electronic structure of monolayer \(\beta\)-TeO\(_2\) plays a critical role in the anisotropy of transport properties for MOSFETs. We show that the 5.2-nm gate-length n-type MOSFET holds an ultra-high on-state current exceeding 3700 {\mu}A/{\mu}m according to International Roadmap for Devices and Systems (IRDS) 2020 goals for high-performance devices, which is benefited by the highly anisotropic electron effective mass. Moreover, monolayer \(\beta\)-TeO\(_2\) MOSFETs can fulfill the IRDS 2020 goals for both high-performance and low-power devices in terms of on-state current, sub-threshold swing, delay time, and power-delay product. This study unveils monolayer \(\beta\)-TeO\(_2\) as a promising candidate for ultra-scaled devices in future nanoelectronics.