Although cloud computing helps learners to access online learning content through commonly used devices, it can be difficult to collaborate in the mobile environment. We develop a service-oriented system, ‘Teamwork as a Service’ (TaaS), to facilitate learners’ team learning activities. The five main services of TaaS facilitate a teamwork-enhanced learning flow associated with the theory of Kolb’s team learning experience, providing learners with an introduction, a ‘jigsaw classroom’, schedule planning, and mutual supervision during the whole process. Specifically, TaaS enables a rational grouping mechanism that allocates learners to their appropriate tasks in order to give their best performance. TaaS is implemented on the Amazon EC2 cloud, and is proven to work with cloud-hosting learning management systems.