In this paper, we focus on early-stage diffusion of co-dependent IT innovations, which are a type of innovation in which the overall innovation consists of two complementary parts that are adopted by two different adopter communities but where both the parts need to be jointly adopted by the two co-adopter communities for successful diffusion of the overall innovation. Using innovation diffusion, organizing vision (OV), and institutional entrepreneurship theories as the key theoretical lenses, and an in-depth case study reconstructed using twenty years of discourse surrounding Walmart’s campaign in the early stages of diffusion of the RFID-in-retailing technology, we develop a four-phase process model for the early-stage diffusion of co-dependent IT innovations. We make three specific contributions to the IS discipline, specifically to the literature on IS innovation adoption and diffusion. First, we add the notion of co-adopter relative advantage and posit that the organization in the co-adopter community with a higher co-adopter relative advantage and which perceives the highest degree of co-adopter relative advantage will emerge as an institutional entrepreneur (IE) and will influence the early-stage diffusion of the co-dependent IT innovation. Second, we add the notion of an internal-external influencer and posit that the IE could be an actor internal to the overall adoption phenomenon, which involves two different co-adopter communities, but who is external to the co-adopter community that adopts the innovation component with lower co-adopter relative advantage. Third, we divide the early-stage diffusion process into four phases – emergence, structuralization, evolution, and chasm – and identify the institutional entrepreneurship strategies used and the OV functions enacted by the IE during each phase. We propose that the IE for a co-dependent innovation will: (1) use the rationale development strategy and enact the interpretation OV function during the emergence phase; (2) use the resource mobilization strategy and enact the mobilization OV function during the structuralization phase; (3) use the relationship development strategy and enact the legitimation OV function during the evolution phase; and (4) use all the three institutional entrepreneurship strategies and enact all the three OV functions during the chasm phase.