The right of choice in marriage is universal and it is enshrined in international human rights instruments. Yet, many girls under 18 years enter into marriage without a chance to exercise that right. This has proved problematic as the situation often results in negative outcomes including school drop-out, pregnancy risks, diseases and sexually transmitted infections, unhappiness, and even death. This study therefore examined the factors influencing child marriage among girls in Nasarawa Eggon Local Government Area of Nasarawa State. It specifically investigated the cultural and sociodemographic factors influencing child marriage among girls in the study area. The ethno-cultural theory of pedogamy guided the study. The mixed method research design was employed with structured questionnaire and key informant interviews utilized in the collection of data. Data was retrieved from 183 respondents, and it was analyzed using quantitative and qualitative approaches. The study hypothesis was tested using Pearson Product Moment Correlation. Results from the study showed that the practice of arranged marriage and beliefs that marriage brings honour to a girl and her family contributes to child marriage. Also, ignorance of fundamental human rights among girls and peer influence, as well as financial difficulties in families, illiteracy among parents and weak enforcement of legal sanctions against child marriage contributes to the practice of child marriage. The study recommends, among others, promotion of education and awareness programme that challenge cultural beliefs that perpetuate child marriage, and implementation of interventions that address poverty in Nasarawa Eggon LGA.