Background: Children who have not received the first dose of a diphtheria-tetanus-pertussis-containing vaccine are classified as zero-dose. Understanding how many children remain without this dose beyond infancy, the correlates, and their geographic distribution can inform routine and catch-up vaccination services in Ethiopia. This study aimed to estimate the burden of zero-dose, identify its correlates, and map its spatial distribution among children aged 12-35 months in Ethiopia. Methods: We analyzed data from 2,097 children aged 12-35 months in the Pathways for Ethiopia survey, a recent national population-based cross-sectional household survey conducted from August to November 2025. The burden estimates and regression analyses accounted for sampling weights, stratification, and clustering. Adjusted prevalence ratios (aPRs) were obtained through marginal standardization of survey-weighted logistic regression models. Spatial autocorrelation, hotspot, and spatial-scan analyses assessed geographic clustering. Ordinary kriging predicted prevalence at unsampled locations. Results: The weighted prevalence of zero-dose status was 20.6% (95% confidence interval [CI]: 15.9-26.3), with regional point estimates ranging from 0.8% in Addis Ababa to 35.9% in Somali. Its burden was 20.4% among children aged 12-23 months and 20.8% among those aged 24-35 months. Higher burden was associated with no antenatal care compared with four or more visits (aPR: 2.39; 95% CI: 1.61-3.53), unimproved compared with improved drinking-water sources (aPR: 1.52; 95% CI: 1.18-1.97), and caregivers rating vaccination as less than very important compared with very important (aPR: 2.68; 95% CI: 2.03-3.54). Zero-dose prevalence showed significant spatial clustering (Morans I = 0.229; p = 0.0001). Hotspots occurred among sampled communities in Somali, Oromia, Central Ethiopia, Afar, and South Ethiopia. Predicted prevalence was highest across parts of eastern and south-central Ethiopia. Conclusion: Approximately one in five children aged 12-35 months had not received the first pentavalent dose. High zero-dose prevalence clustered among sampled communities in eastern and south-central Ethiopia. Moreover, antenatal care and drinking water source were independent factors. Immunization programs should prioritize these communities for identifying and vaccinating missed children, including those aged 24-35 months.