Learning from the partner is considered to be one of the most crucial processes in a joint venture context. Simultaneously numerous advantages of joint venture relationships characterized by trust between partners have been identified. This paper investigates the role of trust in knowledge transfer and assimilation, jointly leading to the learning outcome in an interorganizational context. Propositions linking sources of trust to the processes of knowledge transfer and assimilation in joint ventures are formulated. 2 The growth in the number of strategic alliances since the beginning of the 90’s has exceeded 25 percent annually (Inkpen, 1998). Among these alliances, joint ventures occupy a prominent position. Learning between partners is a crucial aspect of inter-firm cooperation in such form (Hamel 1991; Kogut 1988), whether it is perceived as an opportunity or a liability. The existing literature points to trust as an important variable in interorganizational cooperation. More specifically, a trusting relationship between partners has been suggested to have a positive influence on organizational learning processes (Kostova, 1999). In general, the notion of trust emerges as an important factor for understanding human nature an