Coursebooks exist all over in the world of education. They are generally used as one of the major course materials. To write a coursebook for a particular course is challenging. This study was purposively conducted to develop a English grammar coursebook for teachers to meet the needs of teacher students in English education programs. The study was based on research and development (R&D) with three phases conducted through mix-methods research. In Phase 1, 60 experienced teachers and 226 current teacher students responded to questionnaires that were used to investigate the need for English grammar topics. Sixteen grammar topics that were important to Thai teacher students of English were discovered. In Phase 2, thirty one participants volunteered themselves in a 16-week data collection process. The coursebook was finally developed and composed of 14 chapters including grammar content knowledge, and a variety of exercises including preferable book layouts evaluated by teacher students' needs. In the final phase, Phase 3, three experts contributed by offering their suggestions and recommendations when editing the complete version of the coursebook. The study also found that the coursebook could facilitate learners of all proficiency levels: beginner, intermediate, and advanced, helping them improve their grammar proficiency by a step higher. Ultimately, the study helped illustrate some alternative ways for teachers, lecturers, and authors to compose a coursebook by using a research-based coursebook development process.