One needs higher order thinking skills in positioning perspectives for any kinds of problems that affect one's view of life in order to develop a fundamental scientific understanding. For this reason, science teaching requires thinking skills instruction to be included in classes. This study aimed to observe the effects of student-centered activities, which were formed through scientific argument-centered teaching method, on the critical thinking development of students, comparing it with those of traditional approach in chemistry classes. The research was conducted in two 11th grade classes of a high school in the city of Çankiri in Turkey. Classes were carried out with the teaching approach based on scientific argumentation in the experiment group with 17 students and with the conventional teaching approach in the control group with 17 students. The study lasted for 29 weeks with 11th grade students in two groups. In the experimental group, argumentation-centered instruction activities, which were based on Toulmin's argument model, were conducted. Data were obtained through Watson Glasser Critical Thinking Scale and achievement tests named Achievement Test 1: Reaction Rate; Achievement Test 2: Chemical Equilibrium; Achievement Test 3: Solubility Product; and Achievement Test 4: Equilibrium in Acid-Base Solutions were applied at the beginning and end of the instructions as pre-test and post-test. Wilcoxon test and Mann Whitney U test were used to analyze the data quantitatively. With regard to the results, critical thinking skills of experimental group and control group students made progress, but there was a statistically significant difference between the two groups. Also, when students' answers in achievement tests are analyzed qualitatively in terms of critical thinking subskills, it can be seen that all critical thinking sub skills of the experimental group students have developed more than the control group.