Literature has shown that assessment has various purposes in education, ranging from establishing the starting point, to monitoring and evaluation, while the role of assessment in supporting learning is yet to be explored. In this study I explore the influence of assessment on teaching in the Lesotho junior certificate science curriculum. I achieve this by exploring the nature tools of summative assessment, teachers’ views on these tools and how teachers engage the tools once they have served the summative assessment purpose. In exploring the nature of tools of assessment I conducted a documentary analysis of junior certificate science papers written over three years, and obtained teachers’ views on the papers and their uses through a questionnaire and a focus group interview. The study is predominantly qualitative and interpretive and is informed by three theories; curriculum theory; which explains the cyclic relationship of the curriculum elements, Bloom’s taxonomy which guides the drawing of educational objectives and construction of tools of assessment and social theories explaining reflection on and understanding of one’s social practices. Analysis of the past examination papers showed that they are relatively valid for the syllabus for which they are designed, though there are some discrepancies. Teachers find the questions in the examination papers appropriate for use in teaching, though they need to be simplified at times. The question papers also assess the understanding of science in the context of life around the learner. The uses to which teachers put past examination papers range from planning to testing and the most common uses are teaching and testing. According to the findings, past examination papers do have an influence on what teachers select for teaching and how they approach what they have selected. Further recommendations that I can make on the basis of this study are; that teachers can derive themes for action research from which they can build pedagogical content knowledge for various topics. Finally, they can also be used as a source of a variety of tasks for learners.