This chapter explores key issues in teaching writing to young learners in primary classrooms. It begins by introducing cognitive process theory and genre theory, characterizing writing both as a process involving planning, drafting, and revising, and as a contextualized, purposeful activity shaped by genre conventions. The chapter also underscores the importance of formative assessment and feedback in supporting teaching and learning, highlighting the significant role of targeted feedback, self- and peer assessment, and the use of technology in the writing classroom. Central to effective writing instruction and assessment are learner motivation and engagement, which directly impact students’ writing development. The chapter draws together these theoretical perspectives and discusses their implications for classroom practice.