The diffusion of similar organizational practices across the world has been a prominent research topic for quite some time. In the literature on sociological new institutionalism, two basic research perspectives have developed to address the diffusion and subsequent institutionalization of cultural models and formally organized practices. The first argues that diffusion happens as a top-down adoption process. The second describes diffusion and institutionalization as bottom-up emergence. My stance bridges both perspectives. In this article, I argue that for us to understand (...) diffusion processes, emergence and adoption need to be integrated within a coherent theoretical framework, as both of these processes are inseparably interlinked. The global diffusion of truth commissions is employed as a case study to develop this framework. Starting with the empirical observation of the global diffusion of truth commissions, I dissect the case study by asking: How did truth commissions emerge and become adopted as a globally recognized solution to the problem of dealing with human rights violations after political transitions? To answer this question, I introduce three theoretical building blocks—reciprocal typification, narrative embedding, and fictional consensus. Taken together, these concepts constitute the process of collective learning, which I present here as a new approach to diffusion. (shrink)