This chapter discusses the relationship between assessment and learning, the implications for evidence-based teaching and the necessary conditions for implementing effective assessment, explores strategies for designing and implementing formative and summative assessment and applies assessment principles and practices for planning to teach. Its aim is to encourage primary teachers to embrace their role as assessors in order to monitor and enhance students’ learning progress, as well as measure the impact of their teaching. The relationship between curriculum, pedagogy and assessment is dialectic, meaning each construct is dependent on the others for effective learning to occur. The importance of this phase of planning cannot be under-estimated, as it enables teachers to gather ongoing evidence of their impact on student learning and also provides students with vital information about how to meet the learning goals.