The aim of this study is to investigate the effect of the teaching of subject of Chemical Reactions and Enthalpy based on Common Knowledge Construction Model (CKCM) on grade 11 students’ understanding and their attitudes towards the chemistry lesson. In this study, quasi-experimental method with pretest-posttest control group was used. The sample of this study consists of a total of 54 students, 26 girls and 28 boys, at the 11th grade level. Chemical Reactions Concept Test (CRCT), Chemistry Lesson Attitude Scale (CLAS) and Activity Evaluation Questionnaire (AEQ) were used as data collection tools. The data obtained from the CRCT and CLAS tests were analyzed using an independent sample t-test. As a result of the analysis, it was determined that there was statistically significant mean difference between the experimental and control groups in the post-test averages in favor of the experimental group (t= 0.000; p<0.05). In addition, when the results obtained from the CLAS were examined, it was determined that there was statistically significant mean difference between the averages of the post attitude scale in favor of the experimental group (t= 0.000; p<0.05). The results show that the CKCM has contributed in increasing students’ achievement, understanding and attitudes towards chemistry. More studies related to CKCM should be included and teachers should be encouraged to use this model effectively in their courses.