Background: Patient satisfaction is a multi-dimensional healthcare issue affected by many factors and categorized into those that influence what clients expect of a service as well as those that influence the experience of the service and it may be both influences and be influenced by treatment outcomes. Objectives: To assess level of patient satisfaction and associated factors among patients attending adult outpatient department at public and private hospitals of Hawassa city administration, Sidama regional state, Ethiopia 2023 Methods: Institution based comparative cross-sectional study design used on 730 adult outpatient department (OPD) attendants (369 in public and 361 in private) hospitals of Hawassa city administration. Hospitals were selected by simple random sampling method by using lottery method. And Systematic random sampling method was employed to select study participants. And interviewer administered interview was conducted using kobo collect toolbox for data collection. Statistical package for social sciences (SPSS) version 26 statistical software was used for data analysis. Bivariate and multivariable logistic regression analyses used to identify predictors. The findings were reported using adjusted odds ratios (AOR) and 95% confidence interval. P-value < 0.05 was declared as statistical significance level. Result: Overall patient satisfaction was 76.6% (95% CI: 73.3– 79.5). At the public and private OPDs it was 72.9% (95% CI: 68.3-77.5) and 80.3% (95% CI: 76.5 -85.0), respectively. At public hospital, patient satisfaction was affected by male sex (AOR: 2.00; 95% CI: 1.10-3.61), listening of patients health problem carefully (AOR: 5.13; 95% CI: (1.04-25.23) and provision of clear instruction about prescriptions and investigation (AOR: 2.96; 95% CI: 1.25-6.99). In private hospitals, it was affected by waited <15 minutes to enter the OPD room (AOR: 4.08; 95% CI: 2.03-8.19) and time spent > 15 minutes on consultation at OPD room (AOR: 3.53; 95% CI: 1.64, 7.61). At both public and private hospitals OPDs it was affected by assured privacy (AOR: 3.65; 95%CI: 1.75-7.60) and (AOR: 8.38; 95% CI; 3.41-20.59) and provision of careful examination (AOR: 2.96; 95% CI: 1.25-6.99) and (AOR: 3.70: 95% CI: 1.88, 7.28), respectively. Conclusion: level of patient satisfaction was higher at private hospital OPDs than public hospitals adult OPDs by 7.4%.