Silicate glasses have played a major role as structural and functional materials in human civilization since ancient Egypt. Despite their widespread use and importance in modern society, silica glasses with complex geometries are only fabricated in automated processes using 3D printing. Here, the volumetric printing of silica-based glasses with tunable multimaterial and microstructural control is reported. Volumetric printing enables complex shaping of photo-reactive resins in a few seconds using illumination techniques analogous to those employed for medical imaging. Particle-filled and phase-separating resins are used as photo-reactive feedstock that is quickly printed in 3D and subsequently converted into silica glasses through conventional heat treatment. Using rheology and imaging techniques, it is shown that the design of the resin is crucial to print complex geometries with high shape fidelity. The capabilities of the printing platform are demonstrated by fabricating a silica-based filtration device combining dense and porous glass with tunable compositions in a unique 3D structure.|A multimaterial 3D printing platform for the fabrication of silica glasses with tailored geometries, composition and microstructures is reported. Resin formulations for volumetric printing are investigated for the additive manufacturing of complex-shaped silica-based glasses with multicomponent oxide compositions for applications in microfluidic, catalysis and separation technologies. image