This dissertation defines an architecture for adaptation and metaadaptation in hypermedia systems, using models proposed for the Semantic Web. Adaptive applications are able to alter some of their characteristics, such as its navigation model or presentation model, according to the adaptation context. This context may include information about the user, such as her preferences, navigation history, etc., and about the execution environment, such as access device, bandwidth, etc. Meta-adaptive applications are able to alter both its models and its adaptation process according to the adaptation context. The proposal extends the SHDM model with a context model, adaptation rules and execution architecture. It is shown, by comparison, that the major adaptation models described in the literature can be seen as particular cases of the proposed model and architecture.