ABSTRACT The Common European Framework of Reference (CEFR) is now widely accepted as the standard framework for language competence. The aim of this study, therefore, was to investigate teachers' practises in implementing CEFR-aligned assessments for writing skills in ESL classrooms. The following research questions are outlined: i) How do teachers view the implementation of CEFR-aligned assessments for writing skills in ESL classrooms? ii) How do teachers implement CEFR-aligned assessments for writing skills in ESL classrooms? iii) What issues do teachers face in implementing CEFR-aligned assessments for writing skills in ESL classrooms? iv) How do teachers address the issues they face in implementing CEFR-aligned assessments for writing skills in ESL classrooms? This qualitative study uses multiple case studies, multi-site design and a variety of techniques. Six secondary English teachers, three Heads of the English Language Panel and one School Improvement Specialist Coach (SISC+) from a district in Negeri Sembilan were selected using predefined criteria. Semi-structured interviews and document analysis were used to collect data. The semi-structured interviews were recorded using Google Meet and then transcribed verbatim for analysis. Data were collected through document analysis of teachers' reflective journals (submitted via Google Forms) and existing policy documents from the Malaysian Ministry of Education. A thematic analysis based on Braun and Clarke (2020) was used to analyse the data. ATLAS.ti 9 was used to code and analyse the themes identified by the tools used. This study is essential as it explores teachers' perspectives on one of the key priorities of the Malaysian Education Blueprint 2013-2025, namely the CEFR. Therefore, concerns and solutions were explored to ensure that the implementation of CEFR-aligned assessment is a success that benefits all Malaysian students in achieving the international level of English. The findings of the study show that teachers believe that the CEFR-aligned assessment for writing skills are transformative and applicable. Teachers use three main methods to implement CEFR-aligned assessment: Questioning, CEFR rubrics assessment and peer assessment. At the same time, teachers indicated that time constraint was their biggest challenge and that some of the methods for dealing with CEFR-aligned assessment issues were the guidance they received. The study also provided some recommendations for the Malaysian education system to better train teachers in the assessment of written work. It was found that the answer also leads to the factors influencing the implementation of CEFR-aligned writing skills assessments in ESL classrooms. This study will guide future researchers conducting analytical studies of writing and assessment in secondary English for other grade levels and can be replicated by other researchers in different ESL contexts.