There is a great variation across states in nurse practitioner (NP) scope of practice moderated by state regulations. The purpose of this study was to synthesize the evidence from studies of the impact of state NP practice regulations on U.S. health care delivery outcomes (e.g., health care workforce, access to care, utilization, care quality, or cost of care), guided by Donabedian’s structure, process, and outcomes framework. This systematic review was performed using Medline, CINAHL, PsycINFO, and PubMed according to Preferred Reporting Items for Systematic and Meta-Analysis on the literature from January 2000 to August 2019. The results indicate that expanded state NP practice regulations were associated with greater NP supply and improved access to care among rural and underserved populations without decreasing care quality. This evidence could provide guidance for policy makers in states with more restrictive NP practice regulations when they consider granting greater practice independence to NPs.