INTRODUCTION: Across health care, facility design has been shown to significantly affect quality of care; however, in maternity care, the mechanisms of how facility design affects provision of care are understudied. We aim to identify and illustrate key mechanisms that may explain how facility design helps or hinders clinicians in providing childbirth care. METHODS: We reviewed the literature to select design elements for inclusion. Using a modified Delphi consensus process, we engaged an interdisciplinary advisory board to prioritize these elements with regard to potential effect on care provision. The advisory board proposed mechanisms that may explain how the prioritized facility design elements help or hinder care, which the study team organized into themes. We then explored these themes using semistructured interviews with managers at 12 diverse birth centers and hospital-based labor and delivery units from across the United States. RESULTS: The design of childbirth facilities may help or hinder the provision of care through at least 3 distinct mechanisms: 1) flexibility and adaptability of spaces to changes in volume or acuity; 2) physical and cognitive anchoring that can create default workflows or mental models of care; and 3) facilitation of sharing knowledge and workload across clinicians. DISCUSSION: Facility designs may intentionally or unintentionally influence the workflows, expectations, and cultures of childbirth care.