Wonder weapons is the term given to very advanced weaponry whose design, production or deployment in the field of battle is impractical or ill timed. Such weapons are radical departures or improvements of the arms or machinery used at the time and are often intended to turn the tide of a current conflict. These weapons are either never completed, or are introduced near the end of hostilities in limited capacity so the expectations far exceed the results.

The secrecy surrounding the development of new weapons sometimes conflicts with the weapon developers’ hype of new products resulting in common advancements being mislabelled as Wonder weapons.

The term is often used to describe weapons that were being developed in Nazi Germany just prior to the end of the war, such as the Wasserfall missile, the Messerschmitt Me 262 and the failed German atomic bomb project led by Werner Heisenberg.

Many wonder weapons of the past become the conventional weapons of later conflicts--this has happened to dreadnoughts, tanks, long-range missiles, and might be beginning to happen to tactical nuclear weapons. More recently, offensive developments in electromagnetism with lasers, microwave, or radio frequency radiation are often termed wonder weapons.