Highly prevalent chronic illnesses such as type 2 diabetes can be effectively managed by adhering to certain health behaviors. As such, self-efficacy is a vital factor in this adherence process. This systematic review of cross-sectional studies aims to outline and evaluate the characteristics of the literature investigating self-efficacy and adherence to self-care in the type 2 diabetes population. Eleven eligible studies were identified based on the inclusion criteria after conducting a primary and secondary screening of three major databases (ProQuest, Scopus, and EBSCOhost) from inception to April 2022, along with manual searching from other sources. A narrative synthesis was used to analyze this review. The findings indicated that self-efficacy is significantly correlated with self-care adherence in persons with type 2 diabetes and that higher self-efficacy leads to better self-care behaviors. The selected studies failed to fulfill the quality criteria for identifying and measuring the confounding variables; therefore, future studies should focus on rigorous research design. A more sophisticated approach to elucidate phase-specific self-efficacy and its influence on health behavior among the type 2 diabetic population may be required in the future to design and test theoretical frameworks and intervention studies.