Teacher absenteeism represents one of the major challenges for achieving universal learning in many developing countries, where teacher absence rates range from 3 to 27 per cent. In Tanzania Mainland, available data show that teachers’ attendance is a persistent challenge. According to the 2011-2015 Uwezo Annual Learning Assessment, 18 per cent of primary school teachers of Tanzania Mainland were absent on the day of the 2012 assessment, with substantial regional differences in teacher absentee rates across the country. The World Bank’s Service Delivery Indicators (SDI) survey – piloted in Tanzania Mainland in 2010 and officially implemented in 2014 – suggests that on average, 14.4 per cent of teachers are absent from school and 46.7 per cent are absent from classrooms, and that teachers spend on average 47 per cent of scheduled teaching time on teaching. In addition, the 2011 SACMEQ report reveals teacher absence from school, late arrival and absence from the classroom are common phenomena across the country. While the stark numbers are available, the evidence-base on which factors, policies and practices affect teacher attendance in Tanzania Mainland remains scant. The Time to Teach (TTT) study seeks to address this knowledge gap. The principal objective of the study is to collate and strengthen the evidence base on the various types and factors of primary school teacher attendance and to provide practical recommendations to improve the design and implementation of teacher policies. Specifically, the study looks at four distinct dimensions of teacher attendance: being in school, being punctual (i.e., not arriving late/leaving early), being in the classroom (while in school), and spending sufficient time on task (while in the classroom). TTT is a mixed-methods project, employing both qualitative and quantitative research tools. The study draws from national, system-wide, qualitative data collections and school observations, and a quantitative survey of 259 teachers working in 20 purposely selected primary schools.