Despite the opportunity to improve the quality and efficiency of health services, the adoption rate of Electronic Health Records (EHR) remains low across countries. This study aims to identify previous research contributions to EHR adoption based on the Unified Theory of Acceptance and Use of Technology (UTAUT) model and to explore the relationship between the UTAUT model and EHR adoption. Furthermore, it seeks to identify differences between developed and developing countries. To answer the research questions, a systematic literature review (SLR) was conducted. Additionally, the PRISMA framework was applied in this study to establish a high-quality and transparent process. This study reviewed 13 prior studies in the literature and discovered a lack of research using the UTAUT model in the context of EHR adoption in both developed and developing countries. Moreover, this study discovered various relationships between the UTAUT model and EHR adoption in both types of countries. Behavioral intention appeared as the most significant factor in this SLR, with a greater number of influences than other UTAUT variables in both developed and developing countries.