BACKGROUND:Test anxiety is one of the most disabling disorders and annual school academic performance will affect millions of students. Hence, it needs attention and treatment. Therefore, this research aimed to examine the effectiveness of a mindfulness-based stress reduction (MBSR) therapy on emotion regulation and test anxiety of students and test the remaining effect of this treatment after 3 month.METHODS:Sample size of fifty participants randomly divided into experimental (MBSR) and control groups. The MBSR training interventions were implemented to the experimental group, in eight weekly sessions using MBSR manual by John Kabat-Zinn (2013). Participants in both groups were evaluated using the Test Anxiety Scale and the Cognitive Emotion Regulation Questionnaire. The study findings were analyzed using analysis of variance with repeated measures.RESULTS:The result shows that the MBSR program has had continuous significant effects on test anxiety (P < 000) and emotion regulation (P < 000) but was not significant only for the self-blame subscale (P = 0.126).CONCLUSIONS:The study results indicated that the effects of MBSR lasted through the follow-up, for both of these variables. Using the results of this study may be proposed school counselors use mindfulness to reduce the anxiety of their pupils.