The efforts of the United States government in the past 15 years have included harnessing the power of health information technology (HIT) to improve legibility, lessen medical errors, keep costs low, and elevate the quality of healthcare. However, user resistance is still a barrier to overcome in order to achieve desired outcomes. Understanding the nature of resistance is key to successfully increasing the adoption of HIT systems. Previous research has showed that perceived threats are a significant antecedent of user resistance; however, its nature and role have remained vastly unexplored. This study uses the psychological reactance theory to explain both the nature and role of perceived threats in HIT-user resistance. The study shows that perceived helplessness over process and perceived dissatisfaction over outcomes are two unique instances of perceived threats. Additionally, the results reveal that resistance to healthcare information systems can manifest as reactance, distrust, scrutiny, or inertia. The theoretical and practical implications of the findings are discussed.