a b s t r a c tBackground: One proposed strategy to expand primary care capacity is to use nurse practitioners (NPs) more effectively in health care delivery. However, the ability of NPs to provide care to the fullest extent of their education is moderated by state scope-of-practice (SOP) regulations. Purpose: The purpose of this study was to examine the impact of state SOP regulations on the following three key issues: (a) NP workforce, (b) access to care and health care utilization, and (c) health care costs. Methods: Systematic review. Results/Discussion: States granting NPs greater SOP authority tend to exhibit an increase in the number and growth of NPs, greater care provision by NPs, and expanded health care utilization, especially among rural and vulnerable populations. Our review indicates that expanded NP practice regulation can impact health care delivery by increasing the number of NPs in combination with easing restrictions on their SOP. Conclusions: Findings show promise that removing restrictions on NP SOP regulations could be a viable and effective strategy to increase primary care capacity.