Aim of this study is to identify whether primary school teaching mathematics curriculum implemented by Ministry of National Education in state primary schools in Northern Cyprus. This research was carried out by using survey model. Data were collected by means of the questionnaire which was developed and whose reliability and validity are ensured. Research participants are composed of teachers teaching in primary schools. Collected data were analyzed by using frequency, percentage, independent group t- test, One-Way Anova test and Chi-Square test. Results of the research demonstrate that most of the participants did not receive in-service training about development of critical thinking. Lack of technological infrastructure and material in the school, lack of textbooks and math program prevents critical thinking skills development to classroom teachers’ opinion. Teachers hold view that school administrators should arrange various activities (such as study tours, mathematics competitions, etc.) in order to develop students’ critical thinking skills. Also the development of the technological infrastructure of schools, reorganization of the textbooks and the mathematics curriculum, appropriate learner centered education environments organized in the class provide development critical thinking in the math lesson indicated class teacher. Teachers reported that the mathematics curriculum was devised suitably for developing critical thinking.