Nowadays, many new terms and teaching models are emerging in the field of foreign language teaching/learning. In Differentiated Instruction, which is one of the current teaching models, it is stated that the learner's age, gender, ethnic origin, social life, family situation, both inside and outside the school, makes him/her different from the others. It is also emphasized that this situation should be taken into consideration by teachers during the lesson preparation process and during the lesson. This research is designed with a case study, one of the qualitative research methods. Semi-structured interview form is used in the study in which many interviews are applied. Afterwards, a software program is used for analysing the gathered data and for reporting the findings. In the interviews, the main purpose is to carry out what came to the minds of the instructors as a concept or a definition when this teaching model is mentioned. It is also aimed to determine the experiences of the instructors about this model, their opinions and perspectives on the applicability and necessity of the model. As a result, it can be stated, from the first questions of the study, that the instructors have difficulties in defining this model and some of them apply it in their classes without knowing the name of the model. At the end of the study, it is thought that the interest of the lecturers on the subject will increase and it will have a positive effect.