The aim of this study is to identify the opinions of secondary school mathematics teachers about mathematical modelling. Qualitative research was used. The participants of the study were 40 secondary school teachers working in the Bingöl Province in Turkey during 2012-2013 education year. Semi-structured interview form prepared by the researcher was used for data collection and content analysis using coding method. As a result of the study it has been concluded that knowledge level of teachers regarding mathematical modelling is not adequate, the examples the participants provided for mathematical modelling were in parallel with those in the coursebook, duration of course is not enough for mathematical modelling, mathematical modelling is mostly used for fractions, students' interest increases during the courses in which mathematical modelling is used, mathematical modelling should be included in the program, difficulty level of making mathematical model shows variety from topic to topic.