Enterprise resource planning (ERP) system is the critical software that streamlines processes and allocates internal resources, so firms can make quick responses to the market. However, not all firms can implement it successfully, so usually consultants are used to aid in the implementation process. Client firms expect consultants to transfer implementation knowledge to inner employees; therefore inner employees can contribute to the implementation process and learn how to maintain ERP systems by themselves. This research studies both consultant¡¦s and client¡¦s factors to achieve knowledge transfer in such complex system implementation. Based on prior researches including the antecedents of knowledge transfer and case studies on it, a sender-receiver model is developed. This model suggests that knowledge transfer is founded on proper mechanisms, which are influenced by consultant¡¦s and client¡¦s factors. Data were collected from both consultants and clients, and 175 samples were valid. Unlike prior studies, this model includes the client¡¦s information technology capability and consultant¡¦s agency behavior. The analysis suggests that knowledge transfer is founded on sound mechanisms, which are influenced by bilateral factors. The analysis also provides support for all 5 hypotheses and 12 of the 21 subhypotheses of bilateral factors, and it confirms two moderating relationships. These results (1) adapt antecedents of knowledge transfer and case findings to a sender-receiver model, (2) enhance the goodness of model by integrating antecedents and case findings, (3)incorporate new IS-related constructs and measures in an integrated model. This model can be applied to ERP implementation and other knowledge-outsourced IS contexts.