The present study describes and analyses how social interactions between individual actors form institutional work in the highly institutionalized setting of healthcare organizations. Based on a qualitative case study, we affirm that social interactions mainly form maintaining institutional work, thus primarily upholding the rigidity of healthcare organizations. Social interactions either preserve distance between different actors or prevent their mutual influence, which decreases the effects of institutional complexity. However, when institutional work goes beyond maintaining, social interaction is characterized by processes of claiming influence and granting influence between individual actors who adhere to different institutional logics, which allows effects of institutional complexity. Such institutional work is contingent upon physicians' strong power position, and granting influence is likely to precede claiming influence.