Background: Healthcare systems are becoming increasingly complex. Systems think- ing can help us to understand this complexity and how to apply that understanding to design and evaluate interventions that improve health outcomes. With the current emphasis on developing advanced nursing practice, it is timely to examine systemic processes that characterize ANP systems and their interactions with wider healthcare systems, and how these processes enable and constrain the role. Objective: To make explicit the systemic processes that characterize the Advanced Nurse Practitioner (ANP) system and how they enable and constrain the role. Design: An interpretive descriptive study. Setting: The study was conducted in a large Hospital Group, consisting of eleven acute hospitals, within the Irish Healthcare System. Participants: Twenty nine participants, including ANPs, nurses, nurse managers, medics and allied health professionals, participated in the study. Methods: Data were collected through seven in -depth interviews and four focus groups. Data were analyzed using the Organic Systems Framework (OSF), where attention was on language indicative of the processes of individuation, integration, differentiation and homogenization. Results: Participants emphasize how ANP systems exert power by individuating and differentiating; however, restrictive regulations and medical control constrain this power. Integration and homogenization are expressed as ANPs encourage and engage in collaborative practice towards common purposes. When hierarchical structures and professional self-interest dominate, however, these processes are submerged, re- sulting in unbalanced systems. Conclusion: ANP systems realize their power through increased autonomy by indi- viduating and differentiating. Hierarchical structures positioning ANPs in subservi- ent roles should be challenged. Processes of integration and homogenization are expressed in collaborative practices. We recommend that ANPs realize and articulate the value and diversity that they bring to health systems to strengthen their contribu- tion to them.