Sociocultural factors are important determinants of merger and acquisition (M&A) outcomes. Despite advances in this field, our understanding of sociocultural factors in M&As remains incomplete. In particular, the roles of sociocultural interfirm linkages, HR flexibility, and organizational cultural differences in M&As require further elucidation. The present article contributes to the M&A literature by further clarifying the multifaceted role of these sociocultural factors in M&As. We suggest that sociocultural interfirm linkages (complementary employee skills, trust, collective teaching, and cultural integration) between the merging firms influence the level of knowledge transfer in M&As. Furthermore, we argue that HR flexibility (flexibility in employee skills, flexibility in employee behaviour, and flexibility in HR practices) is vital for the development of the above-mentioned sociocultural interfirm linkages in M&As. Finally, we maintain that organizational cultural differences are important antecedents of HR flexibility in M&As.