The Tanzanian education sector from 1980s has not been performing well particularly on the side of quality and one of the main contributing factors is the economic crisis the country experienced from the early 1980s. At primary school level, for instance, some pupils complete the primary cycle without being able to read and write and lack basic numeracy skills. At secondary school level many students finish the cycle with fourth and zero division in their national Form IV results. Different programmes have been put in place to transform the situation including: the Primary Education Development Programme (PEDP) and the Secondary Education Development Programme (SEDP), and the recently introduced programme, the Big Results Now (BRN).Therefore, the present research project aimed to investigate the preparation and development of secondary school leaders as key implementers of the BRN programme in Tabora Municipality. The study used a mixed research paradigm. The sample included: heads of school, deputy heads, classroom teachers, non-teaching staff, members of School Governing Board (SGB) and the District Secondary Education Officer. Data were collected using focus group, questionnaire and documents. Findings revealed majority of the school heads understood the BRN programme and what is expected from them. However, results showed that many of deputy heads, the teaching and nonteaching staff and members of SGB had little knowledge about the BRN and the School Improvement Toolkit (SIT). Findings indicated further that the majority of school heads, deputy heads, teachers, non-teaching staff and members of the SGB had no training about the BRN. For those who had attended training, results indicated the following areas covered in the training: school accounting procedures; school inspection; procurement procedures; school leadership; mentoring; and staff evaluation. Findings likewise showed that several deputy heads were trained in: Competency Based Teaching (CBT) and methodology of teaching students with visual impairments. Respondents suggested the following essential areas to be focused by the BRN for the successful implementation and sustainability of the programme: capacity building; provision of incentives to the implementers and leaders; adopting the bottom-up approach of planning; and observing professional autonomy. It was generally concluded that, the implementation and sustainability of the BRN programme depends on equipping the implementers with necessary knowledge and skills.