The aim of this study is to investigate The effect of logical thinking skills on the success of mathematics course at the Metacognitive Awareness of Secondary School Students. The research was conducted in the Siirt city centre of Fevzi Çakmak Secondary School with 120 5th, 6th, 7th and 8th grade students in 2018-2019 education year. The data were collected through both Metacognitive Awareness Inventory Schraw ve Dennison (1994) and the Test of Logical Thinking Skills Tobin and Capie (1981). During the research, the collected data were analyzed using Pearson product-moment correlation coefficient, independent samples t-test, and linear regression on SPSS. According to the results, a positive effect is evident the success of mathematics course metacognitive awareness and logical thinking skills. There is a significant relationship between metacognitive awareness and grade point average mathematics (GPAM) scores. In addition, there is a considerable relationship between logical thinking skills and GPAM scores. The research results suggest that metacognitive awareness and logical thinking skills are positive predictors of mathematics academic achievement. Also, it was examined whether mathematics academic achievement, metacognitive awareness and logical thinking skills differ according to gender. Results show that secondary school students' mathematics academic achievement and metacognitive awareness levels differ significantly in terms of gender. Female students are more successful than male students. Besides, female secondary school students' metacognitive awareness levels are higher than that of male students. Also, the significant relationship was found between logical thinking skills with respect to the gender.