Background: Psychiatric symptoms are common in multiple sclerosis. The relationship of emotional state with respiratory function is unclear in these patients. We aimed to evaluate the relationship between the clinical characteristics, anxiety and depression status, and respiratory functions of patients with relapsing-remitting multiple sclerosis (RRMS). Method: The research was planned as a prospective case-control study. Ninety RRMS patients and 50 healthy controls were included in the study. The MS diagnosis was confirmed according to the revised 2017 McDonald's criteria. Disability was divided into two subgroups according to the Expanded Disability Status Scale (EDSS) (under 3.5 and 3.5-5.5). Beck anxiety and Beck depression inventories evaluated. A pulmonary function test was performed with a computerized spirometry device. Forced expiratory volume-1st second (FEV1), forced vital capacity (FVC), FEV/FVC, peak expiratory flow (PEF), maximal expiratory flow (MEF), peak inspiratory flow (PIF), and maximal inspiratory flow (MIF) values were obtained. Results: There were 90 RRMS patients with a mean age of 38.68±10.95 years, and 58 (64.40%) were female in the study. The anxiety and depression scores of the patients were significantly higher than the control group (p=0.02, 0.002). FVC and FEV1 values were lower in patients with higher Beck depression scores (p=0.012, 0.007). FVC, FEV1, MEF50, and PIF values were lower in patients with higher Beck anxiety scores (p=0.002, 0.002, 0.030, 0.027). When EDSS and number of attacks were fixed, there was a low to moderate correlation between anxiety and FEV1-FVC (p=0.001, r=-367, -0.360 respectively), and a low negative correlation between depression and FEV1 (p=0.045, r=-0.214). Conclusion: Anxiety and depression scores are higher in patients with RRMS. Depression and anxiety are particularly associated with low FVC and FEV1 in patients.