Abstract: Scalable 3D-printing of ceramics includes dispensing a preceramic polymer at the tip of a moving nozzle into a gel that can reversibly switch between fluid and solid states, and subsequently thermally cross-linking the entire printed part “at-once” while still inside the same gel. The solid gel, including mineral oil and silica nanoparticles, converts to fluid at the tip of the moving nozzle, allows the polymer solution to be dispensed, and quickly returns to a solid state to maintain the geometry of the printed polymer both during printing and the subsequent high temperature (160° C.) cross-linking. The cross-linked part is retrieved from the gel and converted to ceramic by high temperature pyrolysis. This scalable process opens new opportunities for low-cost, high-speed production of complex 3-dimensional ceramic parts, and will be widely used for high temperature and corrosive environment applications, including electronics and sensors, microelectromechanical systems, energy, and structural applications.