Background: Adequate nutrient intake is an essential part of athletes’ preparation, which results in more effective training adaptation, recovery, better body composition ratios, and improved sports performance. Inadequate nutrient intake or lack of knowledge can lead to disordered eating and eating disorders, the prevalence of which is higher among athletes than in the general population. In most cases, these unwanted outcomes occur because athletes do not seek the help of a qualified dietitian. According to a 2019 report by the International Olympic Committee, disordered eating and eating disorders’ point prevalence ranges from 6% to 45% in women and 0% to 19% in men. In Hungary, no athlete sample has been tested with screening questionnaires for eating disorders, and the development of reliable measurement tools for identifying this problem is also necessary. Objective: The aim of this study is to present the Hungarian version of the DESA-6 questionnaire (DESA-6H) for screening disordered eating among athletes and to investigate its convergent validity (CV), as well as to evaluate athletes’ nutritional behaviors based on comparative study results. Methods: The DESA-6H questionnaire was tested on elite athletes (n = 131) and recreational athletes (n = 123) aged 14 and older. Kendall’s tau-b correlation was used to establish the CV between the DESA-6H and the total EAT-26 score, as well as between the DESA-6H and the three subscales of the EAT-26. The same method was used to test the potential linear relationship between eating behavior questionnaires and weekly training hours. Chi-square tests were conducted to test the relationships between nominal variables. Differences between groups based on age and sport participation levels were analyzed using Kruskal-Wallis H tests, and post-hoc analyses were conducted using Mann-Whitney U tests. Results: The CV analysis showed a significant positive correlation between the DESA-6H and the total EAT-26 score (τb = 0.49, p < 0.001), the EAT-26 Dieting subscale (τb = 0.53, p < 0.001), and the EAT-26 Bulimia subscale (τb = 0.39, p < 0.001). In the total sample, 20.4% scored above the threshold on the DESA-6H, while 40.1% scored above the threshold on the EAT-26. Among sports categories, the highest prevalence was found in aesthetic, weight-dependent, and endurance sports. A significant difference was observed in the DESA-6H scores based on gender (U = 4948.50, Z = –5.210, p < 0.001) and sports participation level (U = 6847.50, Z = –2.123, p = 0.034), with large (Cohen’s d = 0.68) and small ( Cohen’s d = 0.26) effect sizes. The Mann-Whitney U-test showed no significant difference between the 14–17-year-old and 18+ age groups in terms of DESA-6H scores (U = 6082.00, Z = –1.017, p = 0.309). No statistically significant differences were found between the two age groups on the EAT-26 scores either (U = 6490.00, Z = –0.220, p = 0.826). Overall, the statistical tests consistently supported the convergent validity of the DESA-6H when compared with the EAT-26. Conclusions: Based on the results of our research, it can be concluded that the DESA-6H questionnaire is a reliable tool for screening disordered eating among Hungarian athletes. Its application can help in the early detection and prevention of eating disorders.