Systemic innovations require multiple interdependent actors to change their practices simultaneously in order to realize the benefits of the innovation. Building information modeling (BIM) has been classified as a systemic innovation that is adopted by building projects, firms, and users. However, the slow diffusion of BIM in the architecture, engineering, and construction (AEC) sector has maintained the gap between BIM visions and actual BIM practice. Some governments are planning to enact policies to promote BIM adoption in construction. However, in some countries, BIM adoption has already started with large construction organizations (i.e., the middle-out diffusion approach). To learn from previous experience and before enacting top-down interventions, policymakers require a model to stimulate systemic BIM adoption for entire supply chains with fragmented project and organizational structures. The current paper investigates the systemic adoption of digital innovations in construction and is aimed at formulating a model of systemic BIM adoption (MSBA). Three primary datasets consisting of 133 BIM users, 30 chief executive officers, and 20 project managers were collected in Peru and collectively analyzed using cross-classified multilevel modeling (CCMM). It was found that MSBA has five user-, three firm-, and two project-level factors, explaining 28%, 75%, and 50% of the variance in users' BIM adoption, respectively. The proposed model would provide useful guidance for corporate decision makers and government policymakers to develop BIM-diffusion policies to accelerate adoption. It would also provide a useful practical implementation framework as the industry progresses toward a digital mode of working and could underpin further digitalization of the sector worldwide.