Recent years have seen a dramatic increase in the use of commercially produced foreign language course books as core teaching materials in young learner classrooms. In many cases, the approaches taken and the methods advocated in these materials are accepted uncritically by the teachers using them regardless of their teaching context. Teachers in some contexts also do not have a choice and are forced to ‘teach the book’ and implement methodologies that they may not agree with. However, in both cases there is a huge risk of not doing what is best to promote learning. To avoid this possibility a more critical stance towards language learning materials is needed. This paper presents the concept of instructional materials, then presents a classification of teaching materials, importance of instructional materials, some criteria for selection of instructional materials and lastly discusses the general criteria for the evaluation of English Language learning resources.