A company that suffers from low internal integration between corporate functions performs worse than its more integrated competitors, leaving it in a position of competitive disparity. This paper reports on an investigation of the effects of internal integration between purchasing and operations on the mobilization of supplier resources. Low internal integration generates uncoordinated operations and purchasing behaviors that negatively affect supplier resource mobilization. We find that the lack of operations support for eight major purchasing initiatives in a construction company negatively affects supplier resource mobilization, resulting in poor exchange outcomes for the suppliers. Furthermore, different types of uncoordinated behaviors affect suppliers’ resource mobilization in diverse negative ways. Based on the results, we offer a categorization of diverse types of supplier mobilization activities and offer several managerial implications for both buyers and suppliers.