Background: Globally, vaccination is one of the most cost-effective interventions in promoting child survival, preventing 2–3 million child deaths annually from vaccine-preventable diseases (VPDs). In Ethiopia, timely vaccination is stated as key to the prevention of unnecessary childhood mortality from measles, pneumonia, diarrheal diseases, and other VPDs. However, Ethiopia ranked fifth among the ten countries with the most unprotected children. Furthermore, previous vaccine timeliness studies produced widely disparate results. As a result, it was suggested that more research be conducted to investigate the potential factors behind the high proportion of untimely vaccination. Therefore, this study was intended to explore the association between different factors and the proportion of vaccination timeliness administered under the Expanded Program on Immunization in Debre Libanos district, Ethiopia. Methods: A community-based cross-sectional study design was employed from 1 May to 30 May 2021 among children aged 12 to 23 months with their mother/caregiver, who had started vaccination and had vaccination cards in the Debre Libanos. Simple random sampling techniques and pretested semi-structured questionnaires were used for data collection. At last, a multivariable logistic regression was used to identify factors associated with the vaccination timeliness. Result: In this study, 413 children aged 12 to 23 months were interviewed with their mother/caregiver. Overall, 33.7% [95% CI (29.1–38.3)] of children received their vaccines timely. Having a female child [AOR: 2.9, 95% CI: 1.58–5.35], mother/caregiver attending primary [AOR: 6.33, 95% CI: 2.66–15.06] and secondary/above education [AOR: 5.61, 95% CI: 2.41–13.04], sufficient vaccination knowledge [AOR: 3.46, 95% CI: 1.87–6.38], mother/caregiver with least hesitant [AOR: 3.35, 95% CI: 1.51–7.41] and middle hesitant [AOR: 1.89, 95% CI: 1.05–3.58], utilization of ANC [AOR: 2.89, 95% CI: 1.32–6.33], and giving birth at health facility [AOR: 4.32, 95% CI: 1.95–9.59] were the factors independently associated with vaccination timeliness. Conclusion: In comparison to Ethiopia’s existing vaccination coverage, the proportion of children immunized at the recommended time interval is low in the study district. Policymakers should prioritize vaccine timeliness and integrate it into childhood vaccination strategies.
