Abstract: Adolescents often encounter dysmenorrhea, which is a common issue that greatly affects the quality of life for females. A beneficial approach to alleviate dysmenorrhea is through William's Flexion Exercise. This technique is considered one of the most efficient complementary therapies due to its affordability and absence of adverse effects Purpose :to evaluate the effect of William's flexion exercise on menstrual pain, depression and sleep quality among female nursing students with primary dysmenorrhea. Design: A quasi experimental design (One-Group, Time series quasi-experimental design). Setting: The research was conducted at the Faculty of Nursing, Benha University. Sample: A purposive sample of 76 female nursing students. Instruments: Five instruments were used: A structured self-administered questionnaire, Numeric pain rating scale, Patient health questionnaire-9 and Pittsburgh sleep quality index. Results: There was a statistical significant improvement in female nursing students' total knowledge score regarding dysmenorrhea at 4 weeks and 8 weeks post-intervention compared to pre-intervention. As well as, there was a statistical significant improvement in total mean scores of the pain severity, depression level and quality of sleep among female nursing students at 4 weeks and 8 weeks post-intervention compared to pre-intervention. Conclusion: The implementation of William' flexion exercise was effective in reducing level of menstrual pain, depression level and improving quality of sleep among female nursing students with primary dysmenorrhea. Recommendation: It was recommended that William' flexion exercises should be incorporated into as a complementary and alternative therapy into nursing education and curriculum as a method for relieving primary dysmenorrhea.