搜索并歼灭（Search and destroy），是一种在越南战争中被广泛使用的军事战略。简单地说，搜索并歼灭的流程是：利用直升机等垂直起降飞机投放地面部队至指定地点，「搜索」出敌军，「歼灭」之，随即迅速撤退至后方。这种战术的实施很大程度上归功于空骑突袭（air assault）战术的成熟，这是一种基于直升机等垂直起降飞机的全新战术。搜索并歼灭被认为是理想的应对对丛林游击战的战术。与其相对的传统战术是清扫并坚守（clear and hold），简单地说，即「攻击」并占领敌军所在战略地点，（通过修筑战壕等方法）加固之，并无限期地「坚守」该地。从理论上来说，由于单纯的占领土地并不适用与越南战争反**主义联盟一方，美军选择了打消耗战，通过「搜索并歼灭」的战术削弱越共实力。这样一来，死亡人数的对比就成为了检验此战术成果的工具。另外，搜索并歼灭行动往往需要遵守严格的规定。

Search and Destroy, Seek and Destroy, or even simply S&D, refers to a military strategy that became a large component of the Malayan Emergency and the Vietnam War. The idea was to insert ground forces into hostile territory, search out the enemy, destroy them, and withdraw immediately afterward. The strategy was the result of a new technology, the helicopter, which resulted in a new form of warfare, the fielding of air cavalry, and was thought to be ideally suited to counter-guerrilla jungle warfare. The complementary conventional strategy, which entailed attacking and conquering an enemy position, then fortifying and holding it indefinitely, was known as "clear and hold" or "clear and secure." In theory, since the traditional methods of "taking ground" could not be used in this war, a war of attrition would be used, eliminating the enemy by the use of "searching" for them, then "destroying" them, and the "body count" would be the measuring tool to determine the success of the strategy of "search and destroy." It is common practice among military forces to enforce strict rules on a search and destroy mission.