The report presents the headline results from the sixth round of the Uwezo learning assessment survey, carried out in mainland Tanzania in September and October 2015. The majority of children who attend Standard 3 are not proficient at Standard 2 level. It takes primary school children many more years than it should to establish foundational skills in literacy and numeracy. We find evidence that literacy skills in English are significantly lower than those in Kiswahili. This applies to children at all levels of primary school which implies that many children who will join secondary school will find it highly problematic to communicate in English, the language of instruction in secondary schools in Tanzania. There is some evidence that literacy skills in Kiswahili are improving over time – i.e., children in Standard 3 in 2015 show stronger Kiswahili reading skills than children in Standard 3 did in 2012. Teacher engagement in schools remains deficient. While official pupil-teacher ratios appear broadly adequate in government primary schools, the concern is that a good number of teachers are absent from school on a given day. This implies that instruction time during the school day is likely to be low.