Background: Play is critical for the healthy development of elementary school children. Play intervention assists children to reduce aggression tendencies while also build of social skills in a healthy manner. Aim: Assess the effect of play intervention on aggression behavior and social skills among elementary school children. Design: A Quasi-experimental research design was utilized to carry out the current study. Setting: The study was conducted at three governmental elementary schools at Ezbet Elwalda, which is affiliated to Helwan district Sample: A multi-stage random sample of 120 children was taken from three schools. Tools: Included (1) An interviewing questionnaire involved three parts; part I- Child demographic characteristics, part II- Plays data and history of the child, and part III: Aggressive behavior scale. (2) Social skills observational checklist. Results: The mean age ± SD of the children was 11.66±1.6, 51.7% of them were males and one-third of them were in the fifth grade. After the application of play intervention, there was a statistically significant difference in aggressive behavior among elementary school children at (p <0.001). Also, the result revealed that there was a statistical improvement in the mean score of social skills and all its sub-items among the studied sample at (p <0.001). Conclusions: Using play intervention was effective in decreasing aggressive behavior and improving social skills in all items among elementary school children. Recommendation: Continuous education programs should be applied in the school to raise the awareness of school children's parents and the teachers regarding the prevention of aggressive behaviors.