Book excerpt: Despite the emergence of startup accelerators as venture development organizations to high-growth firms, research has yet to identify where these accelerators fit into the venture development ecosystem. By clarifying and reviewing three different subsystems in the entrepreneurial ecosystem, our paper proposes that as an extension of the current incubation mechanism, accelerators contribute to the entrepreneurial ecosystem by transforming entrepreneurs and their ventures at early stages. Drawing upon the Pipeline Model (Lichtenstein & Lyons, 2006), we first plot where the accelerator model fits in the broader entrepreneurship ecosystem, and then demonstrate how different types of accelerators help participating entrepreneurs and their ventures progress along the venture development pipeline. Our theoretical approach contributes to both the entrepreneurship ecosystem and the accelerator literature and provides a practical map for both policymakers and early-stage entrepreneurs to manage and utilize their entrepreneurship ecosystem more effectively.