Background/aim The purpose of the study was to cross-culturally adapt the Multiple Sclerosis Impact Scale-29 (MSIS-29) into Turkish and evaluate its reliability and validity in patients with Multiple Sclerosis (MS). Materials and methods A total of 119 individuals with MS were enrolled in the research. The neurologist classified the patients with Expanded Disability Status Scale (EDSS). In the initial evaluation, patients completed the Multiple Sclerosis Impact Scale-29 (MSIS-29), the Multiple Sclerosis International Quality of Life (MusiQoL), EuroQol-5D-3L (EQ-5D-3L), and Beck Depression Scale (BDS), respectively one week later, the MSIS-29 evaluation was repeated. Internal consistency, test-retest reliability, and construct validity were assessed, separately. Results The mean age of the total sample was 38.2 ± 10.6 years. The test-retest reliability of both subscores of the MSIS-29 was excellent (>0.80). Internal consistency of the MSIS-29 physical and psychological score was 0.968 and 0.914, respectively. Both of the subscores had excellent internal consistency (>0.80). There was a strong relationship between MSIS-29 physical score with MusiQoL, EQ-5D-3L (index), EQ-5D-3L (VAS), and BDS scores (p < 0.01, r > 0.50). MSIS-29 physical was moderately related to EDSS (p < 0.01, r = 0.381). MSIS-29 psychological score was strongly correlated with MusiQoL, EQ-5D-3L (index), EQ-5D-3L (VAS), and BDS scores (p < 0.01, r > 0.50). On the other hand, there was a weak correlation between MSIS-29 psychological score and EDSS (p < 0.01, r = 0.300). Conclusion Turkish version of the MSIS-29 is a reliable and valid tool in individuals with MS.