Background The world is being challenged by the COVID-19 outbreak that resulted in a universal concern and economic hardship. It is a leading public health emergency across the globe in general and developing countries in particular. Strengthening good preventive behavior is the best way to tackle such pandemics. Objective The study assessed preventive behavior and associated factors towards COVID-19 among residents of Qellam Wallaga Zone, Oromia Region, Ethiopia, 2020. Methods A community-based cross-sectional study was conducted with a multistage sampling technique. Data were collected by interview and analyzed using SPSS version 23.0. Binomial logistic regression was used to test the association between the variables. An Adjusted Prevalence with 95% CI was used to express the associations and interpret the findings. Results Among 634 participants, 417(65.8%) were from urban residences, and 347 (54.7%) belongs to a female. Age ranges 18 years through 87 years. Only 68(10.7%) participants showed good preventive behavior for COVID-19. The majority of them (84.7%) perceived that the disease is very dangerous and 450(71.0%) of them believe that they are at high risk. More than 17% of the respondents have sufficient knowledge. Respondents with sufficient knowledge about COVID-19 were about 2 times more likely to exercise good preventive behavior compare to those with insufficient knowledge, [(APR: 2.1; 95% CI: [1.2, 3.9)]. The urban residents was 3.3 more than that of rural residents to practice good preventive behavior, [(APR: 3.3; 95% CI: [1.6, 6.4)]. Respondents who use social media as a source of information were more than 2 times more likely to have good preventive behavior compared to those who did not, [(APR: 2.3; 95% CI: [1.3, 3.4)]. Conclusion Adoptions of COVID-19 preventive behavior in the study population is very low. Due emphasis should be given to rural residents. Risk communication activities should be strengthened through effective community engagement to slow down and stop the transmssion of the disease in the community.