Over the past number of years augmented reality (AR) has become an increasingly pervasive as a consumer level technology. The principal drivers of its recent development has been the evolution of mobile and handheld devices, in conjunction with algorithms and techniques from fields such as 3D computer vision. Various commercial platforms and SDKs are now available that allow developers to quickly develop mobile AR apps requiring minimal understanding of the underlying technology. Much of the focus to date, both in the research and commercial environment, has been on single user AR applications. Just as collaborative mobile applications have a demonstrated role in the increasing popularity of mobile devices, and we believe collaborative AR systems present a compelling use-case for AR technology. The aim of this thesis is the development a mobile collaborative augmented reality framework. We identify the elements required in the design and implementation stages of collaborative AR applications. Our solution enables developers to easily create multi-user mobile AR applications in which the users can cooperatively interact with the real environment in real time. It increases the sense of collaborative spatial interaction without requiring complex infrastructure. Assuming the given low level communication and AR libraries have modular structures, the proposed approach is also modular and flexible enough to adapt to their requirements without requiring any major changes.