Background: Many people's lives are still at danger due to the Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome worldwide. The most crucial sign that antiretroviral therapy has been effective is when the viral load of the human immunodeficiency virus is suppressed to less than 50 copies. There haven't been many researches done in Ethiopia to measure magnitude of viral suppression. Objective: This study assessed magnitude of viral suppression and associated factors among all patients on antiretroviral therapy on follow-up in Sawla, Sodo and Jinka town’s health facilities, Southern Ethiopia. Methods: An institutional-based cross-sectional study was carried out from January 15 to February 7/2023. Based on the number of clients registered, participants were chosen by a simple random sample technique from the public health facilities that have been offering Enhanced Adherence Counseling from the program's inception. In total, 407 patients with human immunodeficiency virus who met the study's inclusion criteria were enrolled. A checklist was used to retrieve data from the patient registration and chart. P-values less than 0.05 with a 95% confidence interval were regarded as statistically significant, and variables with a p-value of less than 0.25 on the bivariable analysis were candidates for multivariable logistic regression analysis. Result: The proportion of patients who successfully suppressed their viral loads was 22.1%. Female participants were 1.79 times more likely to suppress viral load (Adjusted Odds Ratio (AOR) 1.79, 95% confidence interval (CI) 1.02 - 3.13) as compared to males. Patients in clinical stage II had 2.6 times higher chance of suppressing viral load than patients in clinical stage one (AOR 2.60, 95% CI 1.30–5.32). Patients who participated in Enhanced Adherence Counseling sessions for three to six months and above six months were 5.35 and 3.40 times more likely to suppress viral load compared to those who participated for less than months (AOR 5.35, 95% CI 2.04 - 14.00 and 3.40, 95% CI 1.31 - 8.81) respectively. Conclusion: Viral load suppression was low as compared to recommended target. Sex, clinical stage, and participation in Enhanced Adherence Counseling were associated with viral load suppression. It was recommended that healthcare professionals continue to offer Enhanced Adherence Counseling support to all people who have the human immunodeficiency virus.