This research aims to explore the effectiveness of interdisciplinary education program based on multicultural education on the tolerance value, attitude and critical thinking skills of the fourth grade primary school students. Single group pre-posttest design has been used in the study. The research has been carried out with 30 fourth-grade students, at a primary school located within the district of Karakocan in Elazig during the 2015-2016 academic year. Among the participants, 15 are females and 15 are males. The research has employed Tolerance Attitude Scale developed by Kaptan-Yarar, tolerance value and critical thinking story tests and scoring rubrics. Descriptive statistics and dependent samples t-test have been used during data analysis. Research results have revealed a statistically significant difference between critical thinking scoring rubric, tolerance value scoring rubric and tolerance attitude scale pretest-posttest scores in favor of posttest. Based on these results, it can be said that the interdisciplinary curriculum developed based on multicultural education improves students' critical thinking skills, tolerance value and attitudes.