Sol-gel chemistry is a versatile tool for both the preparation and understanding of catalytic materials. The large variety of available synthetic parameters provides exceptional control of the sol-gel product’s structural and chemical properties, and this control allows the catalytic researcher to design for and systematically study the effects of composition, homogeneity, metastable phases, and pore structure on catalytic performance. This review describes the basic relevant issues in the sol-gel preparation of catalytic materials by looking at both single-component and multicomponent systems as well as different products such as aerogels and catalytic membranes. In doing so, we highlight the advantages of sol-gel preparation and illustrate new ideas about and understandings of catalytic materials that it has brought forth.