Research on entrepreneurial ecosystems (EEs) is still advancing as a concept that both practitioners and scholars claim has advanced beyond other approaches to fostering or explaining regional entrepreneurship. However, criticism of the concept centers on a lack of understanding of causes and effects and the importance of single instruments for its functionality. While practitioners and policy makers are jumping on the bandwagon and trying to aim policies directly at entrepreneurial ecosystems, investigation of the role of single instruments and their impact on entrepreneurial ecosystems remains insufficient. Fostering entrepreneurship through startup competitions (SUCs) is a decades-old policy instrument. Today, both scholars and practitioners mention SUCs as an element of entrepreneurial ecosystems, but analyzing them from that perspective remains undone. Building on a regional understanding of entrepreneurship and entrepreneurial ecosystems, this paper provides a novel framework for the role of startup competitions in entrepreneurial ecosystems. Following on previous studies of SUCs, this study identifies core mechanisms and benefits of the competitions and presents a general framework for SUCs. Then, the study results are synthesized with mechanisms central to entrepreneurial ecosystems, e.g., entrepreneurial learning, networks of entrepreneurial-related actors in the region, and financing entrepreneurship. It is argued that startup competitions work as network hubs in entrepreneurial ecosystems because they connect: a) entrepreneurs with each other, b) entrepreneurs with relevant actors (e.g., financiers, experts, entrepreneurship support organizations), c) those actors among themselves. Therefore, the competitions are “anchor events” and strengthen the overall quality of the EE in which they occur. The study also argues that SUCs benefit from a functioning EE’s positive climate for entrepreneurship and the availability of resources. The study is theoretical, and its findings lead to an agenda for further research.