Testicular torsion is a disorder that may cause infertility or subfertility in males. Rosmarinic acid (RA) is a natural polyphenol with potent antioxidant effects that its protective effects in ischemia/reperfusion (I/R) injury in the hepatic, renal, cerebral, and myocardial tissues was demonstrated. The aim of this study was to evaluate the protective effects of rosmarinic acid on testicular torsion/detorsion. 20 healthy male Wistar rats were randomly divided into four groups: sham-operated, torsion/detorsion, rosmarinic acid 50 mg/kg, and rosmarinic acid 70 mg/kg. testicular torsion was performed for two hours and detorsion was maintained for two hours. Administration of rosmarinic acid was performed 30 min before detorsion in treatment groups. Sperm parameters (sperm motility and sperm concentration), oxidative stress biomarkers (MDA, GPx, and CAT), and histopathological damage were examined in all groups. Results indicated that testicular I/R significantly reduced sperm motility and sperm concentration compared to the sham group, while treatment with RA significantly increased motility. Testicular I/R significantly increased MDA level and reduced GPx and CAT levels in the T/D group compared to the sham group, whereas treatment with RA reduced MDA level and increased GPx and CAT levels. Histopathological damages in the T/D group were significantly higher than those in the sham group. RA treatment reduced pathological damages. In conclusion, rosmarinic acid improved sperm parameters, increased antioxidant activity, and reduced histopathological damages. Therefore, it is recommended for attenuating testicular damages.