The purpose of this study was to investigate the effects of royal jelly against radiation-induced oral mucositis in rats. This study was comprised of 48 adult male Sprague-Dawley rats, each between eight and 12 weeks old and weighing 275 +/- 35 g. These were divided randomly into six groups; Group C (control), Group IR (irradiation), Group IR+RJ50 (irradiation plus 50 mg/kg royal jelly), Group IR+RJ100 (irradiation plus 100 mg/kg royal jelly), Group RJ50 (50 mg/kg royal jelly), and Group RJ100 (100 mg/kg royal jelly). The degree of mucositis, the animal's body mass, and food intake were evaluated. Biochemical and histopathological methods were utilized for the evaluation of mucositis, and a hemogram, oxidative stress markers, and biochemical parameters were analyzed. Tongue samples were also processed for histopathological examination. Irradiation significantly increased oral mucositis, decreased the thrombocyte and neutrophil counts, and resulted in a reduction of food intake accompanied by weight loss. In addition, a significant increase in malondialdehyde (MDA) levels and decreased superoxide dismutase (SOD) and catalase (CAT) activities were found (p<0.001). Irradiation plus 50 mg/kg royal jelly caused normalization in the quantitative, biochemical, and histopathological parameters compared with the group that underwent irradiation alone. Irradiation plus 1.00 mg/kg royal jelly did not provide superior radioprotection against radiation-induced toxicities. Royal jelly was administered orally to reduce oral mucositis as it may be more suitably applied.