Abstract The reaction of adolescence girls towards menstruation depends on their knowledge of this phenomenon as a normal physiological process and the essential hygienic practices associated with it. Aim of the present study was to estimate the effect of menstrual educational intervention on performance of institutionalized adolescent girls in El Behiera Governorate. Method A quasi-experimental design was used. A sample of 76 adolescence girls included in the study and data were collected by administering the self-administered questionnaire. Results: The findings revealed that the mean knowledge score of studied girls was increased significantly from (32.99±12.51) before implementation of the intervention to (95.68 ±4.82) after intervention (t=18.367,p < 0.001) and the mean practice score was increased significantly from (55.46 ±8.72) before the intervention to (77.88±7.32 ) after it (t=45.811,p < 0.001). Conclusion and Recommendations: Menstrual education intervention had positive effect on performance of institutionalized adolescent girls. Therefore, it is recommended to implement educational intervention about menstruation through workshops either at governmental and non-governmental residential institutions for care of children deprived from family care.