Absorptive capacity, conceptualized as identifying, selecting and integrating useful knowledge from the environment into commercial applications, is a key capability for any organization, team or individual. While prior literature has made substantial advancement into the performance consequences of absorptive capacity, few studies have addressed what actually constitutes ACAP on a micro level. Thus, there exists a significant gap within the literature concerning the micro-foundations of ACAP. This study attempts to fill this gap by means of multiple case studies within the R&D organizations of three multinational engineering firms. Our findings show how the micro foundations of absorptive capacity are rooted in individual skills, roles and relationships.