Over the course of decades, pedagogical knowledge base for L2 writing teachers and assessment literacy have been widely researched. The present study reviews the related literature, reports the theoretical framework, and presents specific components of L2 writing assessment literacy of both early career and more experienced teachers. The specific components summarized and suggested include why to assess, what to assess, how to assess, and who (i.e., stakeholders) is involved in the assessment. The review focuses on training and raising the awareness of second language writing teachers regarding assessment practices, purposes, and valuing and retaining teachers’ awareness of their beliefs, practices, and pedagogical and assessment knowledge base. Further, we present practical implications and suggestions for early-career teachers.