English language learning is one of the most famous and popular learning destinations and interests for many adults and returning students in the East Asian region, particularly for senior citizens who want to expand their horizon during late adulthood. Although there are many foreign language learning schools, self-learning books, video-oriented materials, and even social media channels for students who want to study an additional language during their leisure time, locating a useful and appropriate textbook or related material is the most important step to increase learner's interests and overall performance. The current study employed a textbook evaluation checklist of a well-known General English textbook material in South Korea. The results of this study indicated the learning behaviours of Korean senior citizens, outlined the application of a textbook evaluation checklist, and evaluated the effectiveness and usefulness of a General English textbook. School leaders, teachers, and department heads can employ this textbook evaluation checklist to evaluate their teaching and learning materials for the appropriateness.