Background: Marriage is a significant and memorable event in one's life cycle as well as the most important foundation in the family formation process. Most studies are done on determinants of age at first marriage using logistic regression but the current study tried to model the survival time of age at first marriage by considering region as a frailty effect. The main objective of this study is to model time to age at first marriage amongst women in Ethiopia. Methods: The data set in this study were obtained from Demography and Health survey conducted in Ethiopia in 2016 E.C. Women‟s work status, religion, place of residence, women education level, access to media, wealth index and desire for more children are variables which were considered as the potential determinant of time to age at first marriage in this study. In this study, we used models to account for the loss of independence that arises from the clustering of women in region of Ethiopia and also we used AIC and BIC to compare different parametric shared frailty models. Results: Of all 15683 women aged 15-49, 11405 (72.72%) were married and the median & mean age at first marriage for women living in Ethiopia were 17 years and 17.25 years respectively, while the minimum and maximum age at first marriage observed were 10 years and 43 years respectively. Based on the result of selected model (Weibull-Inverse Gaussian shared frailty model), place of residence of women, religion of women, education level of women, access to media and desire for more children were significant at 5% level of significance. In contrast work status of women and wealth index were not significant at 5% level of significance. The clustering effect was significant for modeling time-to-age at first marriage dataset and there was heterogeneity among the regions on age at first marriage (θ=0.0463). Conclusion: This study also showed that there was a clustering (frailty) effect on modeling timeto- age at first marriage among women living in Ethiopia due to the fact that heterogeneity in Region from which the women live in, assuming women living in the same Region share similar risk factors related to marriage. Keywords: Time-to-age at First Marriage, Risk Factors, Heterogeneity, Frailty, Laplace transformations