Quality of Service (QoS) is an important feature of a wireless pervasive computing system affecting both services and underlying networks. In a pervasive environment the user?s context and preferences should be taken into account when determining which services to provide and which networks to use. QoS is an important factor in these preferences. However, the mobility of devices coupled with the unpredictability of wireless networks results in fluctuations in QoS as the user moves around or other user traffic varies. To maintain the minimum level of QoS desired by each individual user, a pervasive system needs to be dynamic and adaptive to changes in QoS, if necessary changing the underlying network or services used without involving the user. This paper describes how the user?s requirements for QoS can be met through an architecture in which personalization plays a key role. The architecture has been modeled and a prototype built as a proof of concept for these ideas.