Objective: The objective of this study was to assess voluntary blood donation practice and associated factors among Bale Robe town civil servants in Oromia, Southeast Ethiopia, 2021. Methods: An institution-based cross-sectional study was conducted among 601 civil servants selected by a stratified systematic random sampling technique. Data were collected using a structured self-administered questionnaire. The questionnaire was pre-tested on 5% of the total sample size before actual data collection. Data were coded and entered into EpiData version 3.1 and analyzed using SPSS version 25. Frequency distribution, descriptive statistics, and diagrams were used to summarize and present data. Binary logistic regression was performed to assess the association between independent variables and voluntary blood donation practice. An adjusted odds ratio (AOR) with its 95% confidence interval (CI) was calculated to identify factors associated with the outcome variables. And p-value < 0.05 was used to declare significance. Result: Of the total of 630 selected civil servants, 601 give a complete response to the questionnaire yielding a response rate of 95%. The mean age of participants was 34.19 years, and 328 (54.6%) of them were rural residents before they joined the governmental work. The lifetime voluntary blood donation practice among civil servants was 27%; 95% confidence interval = (23%–31%). The major reason for not donating blood was fear related to blood donation 186 (42.4%). From multivariable logistic regression, four variables were found as significant independent variables associated with voluntary blood donation practice. Accordingly, having a family member or relative who previously donate blood (adjusted odds ratio = 2.48; 95% confidence interval = (1.39, 4.39)), previous participation in a blood donation campaign (adjusted odds ratio = 5.84; 95% confidence interval = (3.39, 1.04)), and willingness to donate blood (adjusted odds ratio = 5.04; 95% confidence interval = (2.21, 11.48)) were variables significantly and positively associated with voluntary blood donation practice, respectively. Civil servants who had no opportunity to donate blood previously were less likely to give voluntary blood donation (adjusted odds ratio = 0.15 (95% confidence interval = 0.063, 0.367)). Conclusion: The study identified a low level of voluntary blood donation. Having family members/relatives who donate blood, previous participation in a blood donation campaign, and willingness to donate blood were significantly associated with voluntary blood donation. Therefore, there should be regularly scheduled campaigns encouraging civil servants’ voluntary blood donation.