This study was carried out to determine the efficacy of the 6th grade mathematics curriculum implemented in 2018 in Turkey using Tyler's model of curriculum evaluation. The study used the survey model and the stratified sampling method. Schools included in the sample were divided into three levels, an "upper group", "middle group" and a "lower group" with regard to their level of success. The research was carried out with the participation of 266 students studying in these schools. The "Middle-School 6th Grade Mathematics Course Achievement Test" was used to determine the level of achievement of the objectives in the curriculum. In addition, the "Attitude Towards Mathematics Scale" was used to determine students' attitudes towards mathematics course. As a result of the research, in terms of the level of achievement of the objectives in the curriculum, it was determined that the students studying in the upper group schools were more successful than the students studying in the middle and lower group schools. Moreover, the upper group students' attitude scores regarding the mathematics course were significantly higher than the middle and lower group students' scores, although the middle group students' attitude scores were significantly higher than lower group students'.