Advancement of Glass-Ceramic Materials for Photonic Applications Glasses, even if often considered a simple, passive, material, constitute an important piece of the photonic puzzle, where active and passive components have to be integrated in order to realize advanced devices able to play with the light at different scales, from the macro to micro and nano. A material group which is known since more than 60 years but was becoming of real interest in photonics only in the last decade is represented by glass-ceramics, namely materials containing one or more crystalline phases evenly distributed within the glass phase. Here a brief overview is presented of the compositions and properties of several glass ceramics, especially in thin-film format, which have been produced starting with a sol-gel process and have exhibited characteristics which are significant for several photonic applications.