A counterattack is a tactic employed in response to an attack, with the term originating in "war games". The general objective is to negate or thwart the advantage gained by the enemy during attack, while the specific objectives typically seek to regain lost ground or destroy the attacking enemy (this may take the form of an opposing sports team or military units).

A saying, attributed to Napoleon Bonaparte illustrate the tactical importance of the counterattack : "the greatest danger occurs at the moment of victory". In the same spirit, in his Battle Studies, Ardant du Pic noticed that "he, general or mere captain, who employs every one in the storming of a position can be sure of seeing it retaken by an organised counter-attack of four men and a corporal".

A counterattack is a military tactic that occurs when one side successfully defends off the enemy’s attack and begins to push the enemy back with an attack of its own. In order to perform a successful counterattack, the defending side must quickly and decisively strike the enemy after defending, with the objective of shocking and overwhelming the enemy. The main concept of the counterattack is to catch the enemy by surprise. Many historical counterattacks were successful because the enemy was off guard and not expecting the counterattack.