Glass is an integral part of the amorphous materials family that has shown great potential in applications ranging from daily life to high-tech fields such as healthcare, architecture, aerospace, and automotive industries due to its hardness, high transparency, and good processability. Compared with traditional systems, hybrid glasses assembled by inorganic and organic units at the molecular level provide more freedom for compositional variation, mass/photon/electron transport, shaping ability, accessible phase transition, and mechanical properties. Owing to the absence of a unique crystallographic unit cell, the nature of glass, as well as the glass transition, is one of the deepest and most interesting unsolved scientific problems. Meanwhile, the dynamics and thermodynamics of glasses are not fully understood because of their structural complexity. This review gives a timely summary of the development of inorganic-organic hybrid glasses during the last few years in terms of materials classifications, design strategies, and synthesis methods together with particularly important photonic applications. Last but not least, we provide a discussion of helpful guidance, perspectives, and challenges for developing high-performance inorganic-organic hybrid glasses.