Birth, pregnancy and death are the standard trio of key events in the life of mankind. Out of these three events, pregnancy is a matter of choice. These compromises their overall development, leaving them socially isolated with little or no education, skills and opportunities for employment and self-realization. These conditions ultimately make married girls susceptible to poverty. Among the objectives of the study the researcher was to identify the different causes early marriages at Kimanya Sub County and to examine the effects of early marriages on the girl child. This study was conducted at Kimanya Sub County in Masaka district. Through the use of random sampling technique, the researcher used a sample size of 370 respondents and data that was collected came from 325 respondents who provided accurate data in relation to the objectives of the study. Summary of the key findings of the showed that majority of the respondents informed the researcher that majority of the respondents presented results showing that adolescent pregnancy was the main cause of early marriages at Kimanya Sub County. This resulted into school dropout as the major effect of early marriages on the girl child. The researcher therefore recommends that there is a need to make maximum sensitization on girl child empowerment in order to make them not to lose morale and avoid getting involved in marriage and there is also a need to employ professional councilors in all the secondary schools in order to make the girl child present their issues such that they would be properly advised.