With independence in 1961, the British system of Parliamentary government, incorporating the principle of responsible government, was formally adopted in Tanzania. But within only one year that system was discarded first, by adopting a Republican Constitution with an executive President in 1962, and then by adopting a one-party state system of government in 1965. The one-party system reached the height of prominence through the concept of "Party Supremacy", and dominated constitutional practice for a whole generation before giving way to demands for greater freedom and democracy through competitive politics in 1992. Throughout this time, however, the preambles to successive constitutions proclaimed that the government in Tanzania was responsible to a freely elected Parliament representative of the people. This thesis traces the constitutional developments in Tanzania during the first three decades after independence so as to assess the extent to which the principle of "Responsible Government" has been maintained. It analyses the adoption of the Republican Constitution with an executive President having enormous powers even to override the Parliament, and tries to show that the one-party system and the concept of Party Supremacy, while appearing to replace Parliament with the Party as the instrument of democratic responsibility, merely served to legitimise the government tendency of holding the people responsible to it, rather than the other way round. While acknowledging the contribution of external influence in reversing that trend and working towards changes for a more responsible and democratic government as signalled by the constitutional amendments of 1992, the thesis highlights some internal factors which have played very important roles in that development. These include the personal contribution of the first President of Tanzania, Julius Nyerere, who, although very dominant, nevertheless had the foresight to reverse his previous positions and welcome a Bill of Rights in the Constitution in 1984, and encourage competitive politics in 1990. The thesis welcomes these latest changes, but still insists on greater popular participation in making a new Constitution and in all future constitution making.