<p>This paper analyzes strategies for platform owners to increase complementor participation on their platform. Specifically, it draws on open innovation (OI) to theorize the impact of three drivers of complementor participation, namely category variety offered on the platform, the extent of boundary resources provided to facilitate complementary innovation, and exclusivity of content offerings. We hypothesize that higher levels of each of these drivers increase the platform’s attractiveness to future complementors and thereby increase complementor participation. Based on negative binomial fixed-effects regressions in the context of video game consoles, we show that category variety has no effect on future complementor participation, while boundary resources and exclusive content do. The results have implications for the orchestration of platform ecosystems.</p>