This study aims to find out the reasons why boys perform better in senior secondary school mathematics examination in Nigeria than girls. It will show the fundamental issues affecting the available facilities for girls in mathematics. The Nigerian society view of girls studying mathematical subjects and taking up careers in mathematics disciplines will be discussed with recommendation on how the differences can be reduced if not possible to remove totally. Implications for future teacher training in Nigeria will be considered. "Measuring the socio-economic position of a 16 year old" is appended. (Contains 14 tables.)