Today, girls’ schooling is one of the most discussed education issues in Africa, especially in Niger. Many discrepancies along gender lines have been pointed out regarding education in Niger. This study is an attempt to explain the transition of girls from primary to secondary school in two regions of Niger. Specifically, it investigated girls’ transition to secondary school and the factors for and against girls’ transition to secondary school in Niamey and Dosso. Data collection methods included document analysis, interviews and questionnaires to regional education decision makers, girl students, teachers and parents. Findings confirmed what research elsewhere has already found out, i.e., girls’ transition was a reality nationally as well as in the two regions. Girls’ transition to secondary school was hindered by socio-cultural and economic factors including the distance from schools and the parents’ poverty but also factors related to the nature of girls as humans such as the outbreak of the periods. Better measures of improving transition of girls in school need to be decided and implemented to help change the situation.