Summative assessment has been identified as an essential element of effective pedagogy. In the New Zealand context, secondary teachers are responsible for summative assessment within their own classrooms and for summative assessment that contributes to standards-based high stakes school leaving qualifications for students. For this they need high levels of summative assessment literacy. However, there is a lack of evidence on the nature of summative assessment literacy and its development, especially in the New Zealand context. A qualitative approach underpinned by an interpretivist research paradigm was used to investigate summative assessment literacy development in eight beginner secondary science teachers. The study tracked the teachers from their entrance to a graduate one-year initial teacher education programme until they had completed six months teaching in their first schools. Each teacher was interviewed at five points through this approximately 18 month period. At each interview they were asked to present artefacts that they felt provided evidence of their understanding and use of summative assessment. These interviews helped establish the beginner teachers’ understandings of summative assessment and allowed them to reflect on what and how they were learning. A questionnaire was used three times during the study (at the beginning and at the completion of the teacher education programme and after six months of teaching). The researcher also observed the students within their university classes. The data was analysed initially using a thematic analysis. Subsequently, a rubric (the SALRubric) was developed to allow further analysis of the development of specific dimensions of summative assessment literacy over time. In the study, summative assessment literacy was found to be an amalgam of knowledges. Teacher commentary indicated that personal and contextual factors acted as amplifiers and/or filters for what teachers chose to implement in practice. Personal factors included teacher prior knowledge, experience, and conceptions about assessment; beliefs about ethical matters; and emotional responses to assessment consequences. Contextual factors included beginner teachers’ interactions and experiences with influential others as well as wider influences such as school policy and practice, and national policy. Beginner teachers attributed their summative assessment development to particular people, learning activities and teaching experiences. The profile of development of their summative assessment literacy was largely idiosyncratic with all beginner teachers demonstrating shifts over time. Development was more evident following practicum experiences. This thesis provides a comprehensive and nuanced view of summative assessment literacy and its development. It highlights the need for policy makers as well as those working with beginner teachers in initial teacher education and schools to take a broad perspective on the nature of summative assessment literacy. A shared understanding regarding its development would allow beginner teachers and those working to support them to better understand the complexity of the process and lead to programmes that better prepare teachers for the challenge of this most complex and important task. The SALRubric developed from this study is a useful tool for tracking summative assessment literacy that could be used by and for beginner teachers to track their development and help focus learning.