Aggressive behavior is a very complicated behavior with a variety of multidimensional causes. In past, social factors were mainly the center of attention for the researchers as causes of aggression in humans. But, with recent scientific and technological advancements, researchers are now trying to explore new areas, including biological factors. The purpose of the present study was to find out the comparison of aggressive Behaviour between government and private senior secondary school boys and girls of Haryana. The sample of the Present study was conducted on total 100 students 50 (boys and girls) of government senior secondary school and 50 (boys and girls) of private schools of Haryana. The age ranged between 15-18 years. Only Aggression behaviour was used to measure ed by Dr. G.C. Pati Aggression test and using statistically analyzed “t’ test method.