Prior studies suggest that open innovation activities positively influence innovation outcomes in large firms. However, few studies have investigated the implications of small and medium-sized enterprises’ (SMEs) adoption of open innovation. We address this research gap by investigating the effects of four inbound open innovation activities on innovation performance of SMEs. In doing so, we draw on data from 252 high-tech SMEs. Our results reveal that different open innovation activities are beneficial for different innovation outcomes. For instance, technology sourcing is linked to radical innovation performance, whereas technology scouting is linked to incremental innovation performance. These findings hold several important theoretical and practical implications.