This research investigates the use and application of quality assurance rubrics and standards for online/blended course design within the context of teaching English for general academic purposes (EGAP). In an attempt to reform an existing blended course of EGAP, the Quality Matters® Higher Education Course Design Rubric (fifth edition) has been used to assure the quality of course design and development from the outset. After the course was implemented with a cohort of undergraduate students at Osaka University, it was peer-reviewed by a certified reviewer affiliated with Quality Matters (QM). The first round of peer review yielded a score of 70 out of a total of 99, resulting in failure to meet several QM standards. Based on the suggestions and recommendations of the reviewer, the course was further revised in terms of content and interface, and it was reviewed for a second time by the same reviewer, this time yielding a full score of 99. This study highlights the importance of quality assurance in online/blended course design and development, particularly in the context of teaching English to university students.