Abstract: In the late 1990s, the unique possibilities application of inorganic nanocrystals with anti-Stokes photoluminescence were demonstrated. In a fairly short period, a significant breakthrough has been achieved in this field due to the development of new and modification of existing methods for the synthesis of these nanomaterials, and the expansion of understanding of the photophysical processes occurring in nanocrystals. The interest from the scientific community is due to the exceptional luminescence properties of upconversion nanomaterials, which can convert photons of the near-infrared spectrum to radiation in the visible and UV ranges. This multiquantum process takes place under low-intensity excitation, which largely determines the use of this class of nanomaterials in high-tech fields, including biotechnology, photochemistry, medicine, solar energy, nanosensorics, etc. The goals of this review are to consider the mechanisms of anti-Stokes luminescence, to analyze the synthesis methods, and to demonstrate the applications of fluoride upconversion nanomaterials, in which they have formed a stable scientific and technological niche.