Catalyst supports are required to meet a wide range of objectives, including chemical purity and composition, optimised surface area/porosity and thermal stability. Gel processing offers means by which many of these requirements can be achieved. In addition, the use of sols of controlled rheology allows the support material to be prepared in a form which facilitates its application to substrates (including metals) as a coating, thereby greatly improving its versatility for producing novel catalysts. The preparation of typical support materials will be discussed, together with examples of their use in catalysis.