Aims: To evaluate the validity of the Korean Migraine-Specific Quality of Life Questionnaire version 2.1 (K-MSQ v 2.1) in patients with episodic migraine (EM) or chronic migraine (CM). Methods: Subjects were recruited from a headache clinic and completed several self-report instruments, including the K-MSQ v 2.1, the Migraine Disability Assessment Scale (MIDAS), the Headache Impact Test-6 (HIT-6), the Migraine-Specific Quality of Life (MSQoL), the Patient Health Questionnaire-9 (PHQ-9), and the Generalized Anxiety Disorder-7 (GAD-7). Some of the subjects were assessed 4 weeks later and underwent the K-MSQ v 2.1 to examine test-retest reproducibility. Internal consistency and test-retest reproducibility were assessed to determine reliability. Construct validity was also assessed. Internal consistency (Cronbach's α) and test-retest reproducibility (intraclass correlation coefficients) were assessed to determine reliability. Pearson correlations were used to determine the validity. Results: For the 180 eligible patients, the value of Cronbach's α for the three dimensions of the K-MSQ v. 2.1 (Role Function-Restrictive, Role Function-Preventive, and Emotional Function) were 0.954, 0.909, and 0.898, respectively, indicating excellent internal consistency. The intraclass correlation coefficients between baseline and the 4-week retest showed reliable reproducibility. The scores of the three dimensions for the K-MSQ v. 2.1 were well correlated with scores for the MIDAS, the HIT-6, the MSQoL, the PHQ-9, and the GAD-7. Internal consistency and construct validity showed similar tendencies in patients with EM and those with CM. Conclusion: The K-MSQ v 2.1 is a reliable and valid screening tool for evaluating QoL in patients with EM and CM. Keywords: chronic migraine, migraine, MSQ, quality of life, validation