Abstract Background: The first visible outcome of the fertility process is the birth of the first child. The first birth marks a woman’s transition into motherhood. It plays a significant role in the future life of each individual woman and has a direct relationship with fertility. The main objective of this study was modeling time to first birth among women in Ethiopia using AFT and multilevel survival models. Method: The data set in this study were obtained from Demography and Health survey conducted in Ethiopia in 2016. Sex of household head, wealth Index, religion, highest education level, type of place of residence, contraceptive use, respondents working status, media exposure, drinking alcohol, age at first sex, age at first cohabitation and number of sibling are variables which were considered as the potential determinants of time to age at first birth. In this study, we used AFT and multilevel survival models (to account for the loss of independence that arises from the clustering of women in region of Ethiopia) and also we used AIC to compare three different models. Result: Of all 15683 women age 15-49, 10274 (65.5%) were give birth and the median age at first birth for women living in Ethiopia were 20 years, while the minimum and maximum age at first birth observed were 11 and 49 years respectively. Based on Log Logistic Gamma shared frailty model), age at first sex, age at first cohabitation, sex of house hold head, type of place of residence, religion, highest education level, contraceptive use drinking alcohol and media exposure were significant at 5% level of significance. Women who use contraceptive method had prolonged age at first birth by a factor of 𝜙 = 1.0501 and women lived in rural area had early age at first birth by a factor of 𝜙 = 0.9492. The variance of the random effect was significant in log logistic gamma shared frailty models (𝜃 = 0.585) Conclusion: The findings in this study conducted have clearly shown that there is variation between regions in time to age at first birth. Educated women, women who use contraceptive had longer survival of time to first birth from their counterpart. But rural women had earlier age at first birth than urban women. Hence, awareness has to be given for the society on age at first birth. The education sector can play on effective role on age at first birth. Keywords: Time to age at first birth, Heterogeneity, Frailty, Fertility, multilevel, AFT vii