Abstract: Groundwater is susceptible to contamination by industrial chemicals, pesticides, and certain minerals, such as fluorinated minerals. Fluorine ion (F⁻) is one of the common pollutants in groundwater, and its excessive concentration may cause harm to water quality and human health. The World Health Organization recommends that the maximum allowable concentration of F⁻ in drinking water is 1.5 mg·L⁻¹, and China’s Sanitary Standard for Drinking Water (GB5749–2022) stipulates that the concentration cannot exceed 1.0 mg·L⁻¹. Therefore, it is extremely necessary to develop effective methods to remove F⁻ from water environment. The adsorption method has the advantages of simple operation, low cost, friendly environment and good effect on the removal of low F⁻ concentration. In recent years, the removal of F⁻ in water environment has been widely concerned. Transition metal oxide nanomaterials are promising new materials for removing F⁻ from aqueous environment due to their good adsorption, high safety, low water solubility and strong desorption ability. In this paper, the current technology of defluorination in water environment is briefly reviewed, and the application of metal oxide nanomaterials in adsorptive defluorination technology is systematically summarized. At the same time, the design and synthesis of metal oxide nanomaterials with higher adsorbability and selectivity are prospected.