This study aimed to develop and evaluate a goal attainment theory-based antiviral agent medication adherence education program (AMAEP) for patients with chronic hepatitis C. A nonequivalent control group pretest-posttest design was used. Data were collected from December 2019 to March 2020 from a control group of 35 outpatients and an experimental group of 28 outpatients older than 20 years old who had been diagnosed with chronic hepatitis C. The data analysis included an independent t-test, a χ2-test or Fisher’s exact test, a Kolmogorov–Smirnov test, an analysis of covariance, and a Mann–Whitney U test. The results showed the effectiveness of the education program for patients with chronic hepatitis C. There were significant differences between the control group and experimental group in patients’ knowledge of chronic hepatitis C (Z = −5.91, p < 0.001), medication self-efficacy (Z = −5.02, p < 0.001), medication adherence rate (t = −3.88, p < 0.001), medication misuse behavior (Z = −5.00, p < 0.001), and patients’ satisfaction with their interaction with healthcare practitioners (Z = −6.61, p < 0.001). Therefore, we hope that the education program developed in this study will be utilized as an intervention for patients with chronic hepatitis C and be further developed for other patients with viral hepatitis.