Social innovation is a fast-growing field of practice that has caught the attention of management and entrepreneurship scholars. The recent excitement surrounding “open social innovation” contests raises the question of what makes social innovation solutions successful contenders in these ubiquitous contests. We used uniquely assembled data, including data generated from external evaluators, to explore what determines success in an open social innovation contest (n = 150 out of 871 entries) in the field of poverty alleviation. We found that innovators who had networks with corporations and those who had commercial orientations were more likely to succeed in open social innovation contests. We also discovered that the perceived usefulness and innovativeness of social innovation solutions mediated these positive relationships. Our study offers early insights that deepen our understanding of success in the growing practice of open social innovation.