This study aims at drawing a conclusion about the use of the first language (L1) in language classes on which there is still no consensus among researchers. In line with this aim, the qualitative studies involving participants' views or practices obtained through interviews or observations were analyzed and then synthesized. Firstly, two basic themes were obtained as "Avoidance of L1 in language classes" and "Use of L1 in language classes". Based on the findings of those studies, the factors such as educational context, the language proficiency of teachers and students, the subject to be taught were pointed out to affect their language choices and also the amount of L1 use in L2 classes. Furthermore, the studies revealed that L1 was used or suggested to be used in various functions which were grouped under three themes as academic functions, managerial functions, and socio-cultural functions. Though no distinct decision to be taken according to the studies analyzed, it can be suggested that L1 may be used if necessary, although language instruction should mostly depend on the target language.