This chapter proposes a new approach for business partner management with ontologies in large business communities. The often postulated adaptiveness and intelligence of new collaborative structures, foremost collaborative networks, require new approaches to deal with the increasing difficulty in handling the resulting complexity of relational ties in communities and business networks. With a growing number of business entities involved in the system, the network management starts to lose overview and control concerning the entities in the pool of partners. Then it seems asked too much establishing, promoting, and maintaining relational ties on a personal basis. A possible solution seems to be support through adequate services of the information and communication technology (ICT) infrastructure. Ontologies offer support for communication processes and complex interactions of business entities in collaborative spaces.