The fourth goal in Sustainable Development Goals (SDG) spells out Quality Education that demands teachers across all disciplines to teach effectively. The available literature suggests that teaching effectiveness starts from good planning, which should be evident in the documentation of lesson plans. However, when it comes to English teachers, their demanding roles that are attributed to the value-laden content, the grading of essays, the performance pressure of high-stake testing, and the requirement of culturally appropriate pedagogies (Loh & Liew, 2016)have (...) caused the practice of writing lesson plans to be challenged, causing the effectiveness of the teaching to be jeopardised. English teachers in international schools are not exempted from facing this problem, yet little studies have been done on the teachers in this context. To achieve the purpose, this research adopts a case study design using document analysis and semi-structured interview to collect the data. The data were analysed quantitatively using a lesson plan rubric by Student Teacher Assessment Instrument (STAI) and thematic analysis, respectively. The study unveils that the teachers had a moderate level of lesson plan, suggesting a need for further support in lesson planning. The findings of this study will be helpful for English. Teachers understand the importance of writing an effective lesson plan as it has a high possibility of enhancing teaching effectiveness. (shrink)