English Language teachers faced problems in assisting their students to attain a higher level of academic achievement. This problem occurred due to their low-level mastery of assessment literacy. Studies show that teachers are unable to assess students accordingly as they lacked the assessment skills and consequently make erroneous decisions. Even more disturbing is that most teachers still have some confusion over the 'what' and 'how' of implementing best classroom assessment practices. The purpose of this study is to review past studies to examine in-service ESL teachers' assessment literacy. As such, there is a dire need to review past studies on assessment literacy frameworks that would facilitate in-service English teachers assessing student learning outcomes and in turn lead to informed decisions and educational policy. The emphasis on social constructivist theory will assist teachers in designing assessment tasks that will involve students to take charge, be responsible to think about their learning through the use of different assessment tools.