Paper Title
Effects of Rational Emotive Behavior Group Counseling on the Assertiveness of Chiang Mai University Students

Abstract
This research aimed to study the effects of Rational Emotive Behavior group counseling on assertiveness of Chiang Mai University students. The research samples consisted of 16 undergraduate Chiang Mai University students, who volunteered to participate in the Rational Emotive Behavior group counseling. By utilizing a simple random sampling method, the subjects were divided into an experimental group and a control group; each group comprised 8 students. Consequently, the experimental group attendedthe Rational Emotive Behavior group counseling, whereas the control group did not. T-test was employed to analyze the data. The research results were as follows: 1. The students who attended the Rational Emotive Behavior group counseling had significantly higher assertiveness than before attending the group counseling at the .01 level. 2. The students who attended the Rational Emotive Behavior group counseling had significantly higher assertiveness than before attending in comparison to the students who did not attend at the .01 level. In conclusion, applying the Rational Emotive Behavior group counseling could effectively increase the Chiang Mai University students’ assertiveness. Additionally, the qualitative information was discussed with the results to confirm the efficiency of the Rational Emotive Behavior group counseling in an empirical manner. Keywords - Group Counseling, Rational Emotive Behavior Group Counseling, Development, Assertiveness, University Student