Appropriate infant feeding is crucial to ensure optimal child growth and survival. We aimed to assess infants' breastfeeding and complementary feeding practices from 0 to 12 months in Ethiopia. This study was a secondary analysis of data from the Ethiopia Performance Monitoring for Action panel study performed from July 2020 to August 2021. One thousand eight hundred and fifty infants were included from five Ethiopian regions: Addis Ababa City Administration, Oromia, Amhara, Afar, and Southern Nations, Nationalities, and Peoples Regions. Appropriate infant feeding practices were assessed using the World Health Organization measurement criteria and descriptive analysis. One-year-old infants were considered to have a diversified diet if they had complementary feeding comprising five or more food groups. Two-thirds (67%, 95% CI: 63, 71) of newborns were put to the breast within 1 h after delivery. The median duration of exclusive breastfeeding was 6.5 months, and 69% (95% CI: 67, 71) were exclusively breastfed at 5 months. Almost all (97%; 95% CI: 96, 98) were still breastfeeding at 12 months. Sixteen percent (95% CI: 13, 19) of infants (boys 15%, girls 16%) aged 12 months had a diversified diet, and 49% (95% CI: 44, 55) consumed sugary foods or beverages. Most Ethiopian infants had appropriate breastfeeding practices, while almost all had poor-quality complementary food at 1 year. Increasing access to high-quality education on infant feeding is crucial to maintaining and enhancing appropriate breastfeeding practices and complementary food quality. Intensifying poverty reduction efforts are essential to improve infants' dietary diversity and nutrient-dense food consumption.