Research has shown that both product-process technology (PPT) integration and supply chain integration efforts produce operational benefits, yet synergies between these types of integration are not well understood. This article empirically examines strategic customer integration and supplier integration as complementary activities for PPT integration, with the aim of helping manufacturing plant managers to intelligently implement mutually supportive types of integration. We set two conditions for establishing complementarity: (i) one type of strategic integration must positively influence the adoption of another and (ii) the two types of strategic integration must exhibit a synergistic fit with respect to manufacturing plant capabilities. We test these conditions using survey results representing 224 manufacturing plants. The findings show positive complementarities between PPT integration and supplier integration with respect to quality, delivery, and process flexibility. Also, positive complementarities exist between PPT integration and customer integration with respect to quality and new product flexibility. The results extend the emerging theory of strategic value chain integration and provide guidance to manufacturing managers who wish to assemble strategic integration policies.