Social networks have been widely recognized as important factors in determining innovation outputs. Although a significant body of research has examined the implications of board interlocks for the diffusion of strategy-related knowledge, little attention has been paid to the relationship between board interlocks and corporate innovation outputs. To address this gap in the literature, I draw upon insights from social network research and argue that board interlocks do affect corporate innovation. Further, many board interlocks bridge an individual's primary affiliation (day job) and their secondary affiliation as a director. Given the different primary roles of individuals who create interlocks, I further propose that different interlocks have varied effects on the exploration of new technologies. I test these hypotheses by analyzing information from multiple resources, including historical records of board appointments and data on technological innovations from U.S. public companies. Results provide strong evidence that board interlocks are important for focal firms seeking to explore new technologies, and that knowledge flow is asymmetrical for different types of interlocks.