This study aimed to determine the effect of periodontal disease and dental decay, which deteriorated oral health in athletes, on the respiratory system and hence sports performance. The athletes were divided into 3 groups: group 1: no periodontal disease or dental health problem (age: 16.8 ± 4.72 years; 10 male and 15 female); group 2: DMFT 1.7 and 13 athletes with periodontal disease (age: 18.2 ± 4.88 years; 22 male and 22 female); and group 3: DMFT 6.7 and periodontal disease (age: 20.8 ± 4.60 years; 19 male and 23 female). The mean prevalence value, DMFT index, gingival index (GI), forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) ratio, and FVC mean value were evaluated. The mean FEV1/FVC% value of group 1 was 84.8 ± 2.26, and the mean body mass index (BMI) was 20.8 ± 4.56. The DMFT index of group 2 was found to be 1.7. Based on the GI assessment, 13 athletes were diagnosed with acute gingivitis. The mean BMI of this group was 22.2 ± 3.49. Based on the respiratory test, the mean value of FEV1/FVC% was 85±2.22. The DMFT index of group 3 was 6.7. No significant correlation was found between FEV1/FVC% and oral health problems of group 2. However, a significant correlation was observed between FEV1/FVC% and oral health status of group 3. FEV1/FVC% decreased with poor oral health, indicating that respiratory values were affected when oral health was bad, influencing the athlete's performance negatively.