Based on a well-recognized formative assessment strategy model (Leahy et al, 2005) and multiple analytical frameworks of teacher feedback, the present study investigated three teachers (a novice, an experienced, and a veteran teacher) with regard to their instructional, assessment, and feedback practices throughout the pre-, during-, and poststages of a second language (L2) writing instruction cycle. Adopting a case study approach, multiple data were gathered from interviews, lesson observations, teaching materials, students’ writing, and teacher written feedback. Cross-case comparisons were conducted to understand teachers’ formative assessment strategies, feedback practices, and their difficulties. The study found that the teachers engaged primarily with the pre- and post-writing stages. In the pre-writing stage, they conducted a variety of activities to prepare students for writing and to clarify target writing criteria. However, they tended to skip the during-writing stage. In the post-writing stage, all teachers adopted comprehensive error correction with the novice teacher giving more corrections than the other two. Only the experienced teacher required students to compose a second draft, the other two requiring only a single draft. Unlike the veteran teacher, the two younger teachers avoided writing negative comments and wrote many personalized comments probably in order to build relationships with students. In terms of feedback orientation, teachers paid more attention to what a student did and could do better in the task at hand than what a student could do in future tasks. Implications drawn from this research were presented in the form of a checklist for teachers, which integrated instructional and formative assessment strategies with the L2 writing instruction processes. Copyright © 2019 English Language Education Publishing.