Purpose: The purpose of this study was to identify factors influencing health behavior compliance in adult patients with moyamoya. Methods: A descriptive correlation study was conducted to investigate the factors influencing health behavior compliance. Participants were 142 adult patients diagnosed with moyamoya disease who were hospitalized or visited an outpatient clinic in the Gyeonggi province. Data were collected from December 16, 2019 to April 14, 2020 using self-report questionnaires and analyzed using the IBM SPSS 26.0 Win software. Results: The hierarchical multiple regression analysis demonstrated that self-efficacy (β = .60, p < .001), social support (β = .13, p = .032), and age (β = .21, p = .005) affected the health behavior of adults with moyamoya disease. These 3 variables explained 62.0% of the variance of health behavior compliance, and the most influential factor was self-efficacy. Conclusion: Based on the results of this study, it concludes that nursing interventions should be focused on self-efficacy and social support to improve health behavior compliance with adult patients diagnosed with moyamoya disease. For that, various strategies to enhance self-efficacy and social support should be developed and actively applied in the clinical setting for adult moyamoya patients.