Introduction: Hand washing through appropriate and easy methods and educational intervention could be save millions of lives, which are cost effective in many developing world. There are clear changes observed in hand washing behaviors of primary school children after the educational intervention. Hand hygiene is the cornerstone for prevention and control of infection and prevents the children from different diseases. Methods: A quasi- experimental, quantitative, before and after study design was conducted among the students total (n= 76) in the primary school of Ali Raza Abad Raiwind Road Lahore, Pakistan from September 2018 to December 2018. The educational intervention involve four meeting about hand washing in which the researcher educate the students about hand washing practices and give standard knowledge that improve the hand washing practices that lead to prevention of disease which are caused by contaminated hand and appropriate way of hand washing to promote the good quality of health. Results A total 76 children participated in the study, the majority of the participants were boys 53(69.74%). The mean score of knowledge before intervention is 13.3816, standard deviation is 3.54675 and standard error of mean is .40694 on the other hand the total means of knowledge after intervention is 18.6447, standard deviation is 1.52930 and standard error of mean is .17542. The mean difference between the two mean is 5.26316. There is a statistically significant difference before and after the educational intervention. The educational intervention is highly effective because the significant value is 0.00. Conclusions: The result of the study shows the knowledge regarding hand washing practices of children in primary schools was improved after educational implementation and by proper techniques of hand washing.