Abstract: The aim of this study is to examine "The Influence of the Critical Thinking Skills on the Students`Achievement". An experimental method is employed in the study. "Achievement Test" was applied to the experiment and control groups before and after the application of the programs. The study is designed according to the model with "pre-test, post-test control groups". Using the cluster sampling, 50 students are selected; 25 for the experiment group and 25 for the control group. The KR-20 reliability coefficient of the test using in the study was 0.73 and the difficulty of the test was 0.44. In conclusion, the students in the experiment group were more successful than the students in the control traditional group through use of the critical thinking skills which are learnable.