Background: Vaccine is crucial for prevention of an estimated 2 to 3 million global deaths each year from vaccine preventable diseases. Vaccine timeliness is important to prevent child death and morbidity. According to the 2016 Ethiopian Demographic and Health survey report 1 out of 15 Ethiopian children die before reaching age five due to vaccine preventable disease. So we assessed age-appropriate vaccinations coverage and associated factor among children 12 to 23 months of age in Ankesha Guagusa district, northwest Ethiopia. Methods: A community-based cross-sectional study was carried out from September to October, 2021 in Ankesha Guagusa district among 403 mothers/caregivers who had children 12 to 23 months of age by using simple random sampling technique. A face-to-face interviewing and document review with pre-tested questionnaire were used to collect data from each participants. Data were enter into Epi-Info7 software and exported to SPSS-23 for analysis. Bi-variable and multivariable logistic regression analysis were done. Factors with a p- value of < 0.05 in multivariable analysis was considered as independent determinants age appropriateness vaccination coverage. Results: Age appropriate vaccination coverage among children was 7.7% (95% CI: 5.0 to 10.4) for BCG, 30 %( 95% CI: 25.6 to 34.7) for pentavalent 1, 28.3% (95% CI: 24.3 to 33.5) for pentavalent 2, 24.8% (95% CI: 20.4 to 29.3) for pentavalent 3 and 26.8 %( 95% CI: 22.1 to 31.0) for measles. Age appropriate vaccination of pentavalent 1-3 and measles vaccination was associatedwithrural residence of pentavalent one (AOR:0.138, 95% CI:0.058-0.332),uneducated mother/caregiver for pentavalent two (AOR: 0.328, 95% CI: 0.137-0.787),increased household family members(>5members) for pentavalent two (AOR:0.55, 95% CI:0.34-0.90), lack of knowledge about vaccine side effect for pentavalent two (AOR:1.69, 95% CI:1.03-2.76), pregnant women not participated in conference pentavalent three (AOR:2.53, 95% CI: 1.29-4.94). Conclusion and recommendation In this study area, age-appropriate vaccination coverage proportion of BCG, pentavalent one, pentavalent two, pentavalent three and measles were low. The identified findings will be important to improve age appropriate vaccination coverage by focusing on timeliness. Focusing on repeatedly aware on age appropriate vaccination and encourage mothers/caregivers to recognize the appointment day of each vaccine to increase timeliness vaccination coverage should be recommended. Keyword: BCG, Pentavalent, Measles,Vaccination, .