Abstract: For the rapid progress of Internet technologies in recent years, Electronic Commerce (EC) has gained attention as a major theme for enterprises to keep their competitiveness. From the perspective of effective resources utilization, it becomes now an important group for an enterprise to promote its performance and competitiveness through integrating itself and relevant suppliers and consumer as a virtual goal to achieve the so-called Business-to- Business EC. In this paper, we propose an object-oriented modeling approach that addresses the management of collaboration on the Internet between enterprises. The approach divides those required mechanisms for collaboration management into three layers: commitment, role, and activity ones. With this architecture, two enterprises may collaborate via the establishment and maintenance of commitment, the collaboration and coordination between roles and the interaction and coordination between activities. For specification, an object-oriented model is presented for each layer that describes the working details of that layer. To illustrate, these models are applied in a simplified supply chain management among various enterprises.