We explore the extent to which state scope of practice laws are related to nurse practitioners (NPs)’ day-to-day practice autonomy. We found that NPs experienced greater day-to-day practice autonomy when they had prescriptive independence. Surprisingly, there were only small and largely insignificant differences in day-to-day practice autonomy between NPs in fully restricted states and those in states with independent practice but restricted prescription authority. The scope of practice effects were strong for primary care NPs. We also found that the amount of variation in day-to-day practice autonomy within the scope of practice categories existed, which suggests that factors other than state scope of practice laws may influence NP practice as well. Removing barriers at all levels that potentially prevent NPs from practicing to the full extent of their education and training is critical not only to increase primary care capacity but also to make NPs more efficient and effective providers.