Immersive Web (IW for short) applications such as Second Life and SimCity are increasingly popular among individual users and companies. However, it is difficult to build a hybrid Immersive Web application, because of the different architectures used for building such IW applications. In this paper, we propose a service-oriented framework to support the mashup of heterogeneous IW applications for hybrid IW applications. We first model each object in IW (e.g., a virtual album or a virtual room) as an IW Object Service (IWOS) located by a unique URL with standardized service interfaces. As such, one IW application can use an IWOS instance in another IW application. Moreover, non-IW applications (e.g., an online album system) can also access an IWOS instance via its service interface. We further propose a service-oriented framework to manipulate these IWOS instances, to support the transition of these objects mainly between different IW applications, and to enable the transition between IW applications and non-IW applications. Our framework also includes the fundamental services to build hybrid IW applications. Finally, we provide examples to demonstrate the advantages of our framework, and conduct a qualitative analysis to show the effectiveness. © 2011 IEEE.