Abstract—: The paper describes the current state of fiber-optic gyroscope (FOG) development. An overview of the modern gyroscopic market for inertial navigation is made with a special focus on the FOG niche. The principle of operation is briefly described; classification of existing FOGs is presented; their advantages and disadvantages are discussed; and some examples are given. Key Russian and international manufacturers are mentioned in the paper. Finally, trends of FOG development are analyzed, and the future development of the gyroscope market is assessed. © Pleiades Publishing, Ltd. 2023. ISSN 2075-1087, Gyroscopy and Navigation, 2023, Vol. 14, No. 4, pp. 277–289. Pleiades Publishing, Ltd., 2023. Russian Text The Author(s), 2023, published in Giroskopiya i Navigatsiya, 2023, No. 4, pp. 3–21.