The issue of language of instruction (henceforth LOI) in Tanzania secondary education has been researched and debated for over four decades but the debate is becoming more controversial as we move into what the elite call ‘the era of globalisation’. The controversy is on which of the two languages, Kiswahili or English is the appropriate choice as LOI from secondary school to tertiary education in Tanzania. In 2009 the Ministry of Education and Vocational Training proposed a new Education and Training Policy that requires English to be LOI from nursery school to tertiary education. This proposed policy contradicts research findings and is insensitive of the sociolinguistic realities of Tanzania. As a result, I have been prompted to revise an earlier version of this paper (Qorro, 2008) and to review studies on the LOI issue in the light of the recently proposed education policy in Tanzania and to discuss the different alternatives suggested by these studies in addressing the LOI problem.