Non-prescribed drug utilization is the act of using medication to treat self-diagnosed problems without consulting a healthcare provider. Pregnant women are among the most vulnerable population groups for self-medication to treat pregnancy-related problems. The use of non-prescribed drugs, however, has numerous detrimental effects on both the growing fetus and the mother. Besides, community-based information regarding the pattern of non-prescribed drug use is limited in Ethiopia. Hence, this study aims to investigate non-prescribed drug use and its associated factors among pregnant women in Jimma town, southwest Ethiopia, in 2023. A community-based cross-sectional study was conducted among 358 pregnant mothers in the peri-urban kebeles of Jimma town, southwest Ethiopia. A systematic random sampling technique (every K = 3 households) was used to select the final study participants. Data were collected using an interviewer-administered structured questionnaire, entered into EpiData version 7.2.2 software, and exported to SPSS version 25 for further analysis. Both bivariable and multivariable logistic regression models were fitted to identify the factors influencing non-prescribed drug utilization status. The level of significance of the association was determined at a P-value < 0.05 with a 95% CI. A total of 358 (99.4%) pregnant women participated in the study. The mean age of the participants was 25.06 years (Standard Deviation ± 4.25). Overall, the prevalence of non-prescribed drug use among pregnant women was 37.7% (95% CI: 32.8-41.7%). The most common reasons for using non-prescribed drugs were the easy availability of these drugs in pharmacies and drug stores, followed by their relatively low cost. Enrollment in health insurance (AOR = 0.21, 95% CI: 0.03-0.76), being primigravida (AOR = 3.05, 95% CI: 1.03-5.08), and experiencing pregnancy-related complications (AOR = 2.34, 95% CI: 1.99-2.76) were found to be significant factors influencing the utilization of non-prescribed drugs among pregnant mothers. In the current study, non-prescribed drug use among pregnant mothers was high. Health insurance enrollment status, gravidity, and the presence of any pregnancy-related complications were identified as significant predictors of non-prescribed drug use among pregnant mothers. Hence, stakeholders should invest their efforts in increasing community enrollment in health insurance programs and place special emphasis on high-risk groups prone to non-prescribed drug use.