In recent years, the use of (or lack of) of English textbooks in teaching English as a second/foreign language classrooms has become an issue of great debate among English teachers. Regarding the critical role of teaching materials in second language instruction, this study was an attempt to evaluate the English Coursebook taught at the 10th grade in Afghan schools from the perspectives of both teachers and students. To this end, 30 Afghan teachers of English were asked to fill out a piloted, Likert-scale questionnaire whose items tapped different aspects of the book. In addition, 100 Afghan students at the 10th grade were given another questionnaire to elicit their opinions on the book. After collecting and analyzing the data, the results indicated that, except for the pictures and illustrations used in the book, other aspects including ‘meeting syllabus objectives’, ‘compatibility with Afghan socio-cultural norms’, ‘teachability’, and ‘effectiveness of the testing system’ are confirmed by the teachers. In addition, except for the paper quality and suitability of the illustrations and pictures, the students agreed on the effectiveness of the book in vocabulary development, topic selection and sequence of the exercises.