This study examines the relationship between age at first marriage and women’s fertility behavior and empowerment. Data were extracted from the 2013 Nigeria Demographic and Health Survey. The Poisson regression and multinomial logistic regression were applied using Stata version 12. Results show that the incident rate of children ever born for women aged 15 to 19 years is less than the incident rate of children ever born for women aged 14 years or less (incident rate ratios = 0.8177, p < .01), and that the relative risk of being in high empowerment category instead of moderate category will increase by a factor of 2.0988 for those aged 15 to 19 years at first marriage compared with those aged 14 years or less. Age at first marriage is significantly related to women’s fertility behavior and empowerment.