This paper describes Web service composition as a form of teamwork, where the Web services are team members in a loose collaboration. We argue that newer hierarchical teamwork models are more appropriate for Web service composition than the traditional models involving joint beliefs and joint intentions. We describe our system for developing and executing Web service compositions as team plans in JACK Teams,((TM) 1) and discuss the relationships between this approach and service orchestration languages such as Business Process Execution Language for Web Services (BPEL4WS). We discuss briefly how the use of Al planning can also be incorporated into this model, and identify some of the research issues involved. Incorporating Web service compositions into a mature Belief Desire Intention (BDI) agent team framework allows for integration of Web services seamlessly into a powerful application execution paradigm that supports sophisticated reasoning. Crown Copyright (C) 2006 Published by Elsevier Ltd. All rights reserved.