The thesis investigates if the use of a reserve seat system of parliamentary quotas that has produced a substantial descriptive increase in the number of women in the Tanzanian parliament has translated into substantive representation for women in terms of either process or outcome. It utilized the Tanzanian parliamentary database as its primary source of empirical data. From this it draws biographical details on the members of the parliaments, their membership of committees and their contribution to parliamentary debates. The study finds that the increase in the number of women has not produced a significant enhancement of substantive representation. Although women contribute as frequently as men to the parliament they are disadvantaged in terms of their occupation of positions of leadership as they have a lower level representation in the ‘prestige’ ministries and committees. Also debates on the issues of direct concern to women remain at a very low level both in term of the volume of contributions and the progressiveness of the content. However the overwhelming majority of contributions on women’s issues are made by women. The small number of contributions made by men tends to be of a conservative nature seeking to limit women’s freedom of choice and action. In addition to this in contradiction of some of the current literature, the thesis found no evidence that the reserve seat system was a pathway for women into constituency seats.