Staff development is crucial as it equips workers with life long survival skills on their jobs. Staff development also bridges the gap between the teachers’ available acquired skills and the new teaching skills required in the curriculum. Staff development is therefore concerned with the expansion of knowledge and skills of teachers so that they contribute to their growth in relation to their jobs and improve student learning through enhanced performance by the teachers. This study sought to evaluate the effectiveness of school based staff development programmes in Zimbabwean secondary schools using the quantitative paradigm. The study employed the survey descriptive design. The target population comprised all schools in Gweru District using a sample of 220 teachers and heads composed of 112 females and 108 males. All the information was collected using a questionnaire which had both close-ended questions and open-ended questions. The study revealed that lack of follow up evaluation sessions to staff development programmes affect the effectiveness of staff development design and implementation. The study also revealed that time allocated to staff development programmes was not adequate resources. The study recommends that there should be adequate resources to effectively plan and implement staff development programmes and that staff development programmes must be allocated enough time for them to be effectively carried out.