A pike is a pole weapon once used extensively by infantry principally as a counter-measure against cavalry assaults. Pikes were extremely long weapons, carried by infantry and resembled a spear between 10 and 14 feet long. These eventually grew in size both in shaft and head length; the awl pike could exceed six metres in length.

The steel tip was fairly long compared to the shaft, making the weapon most unwieldy in close combat. This meant that pikemen were often equipped with a sword for close encounters.

In operation on the battlefield, pikes were often used in large square "hedgehog" formations. For example, the Scots used highly disciplined units of pikemen called schiltrons to defeat English knights and heavy cavalry at the Battle of Bannockburn in 1314. Large pike formations, sometimes defending attached musketeers, were in use during the 17th century, but were eventually rendered obsolete by the bayonet and the demise of the cavalry charge in the face of more effective firearms such as the flintlock musket.

The landsknechts were pikemen of renown during the 15th to the 17th centuries, mercenaries of the European Renaissance. They were most skillful in their handling of the long pike.

Retroactively most very long spears are today called pikes, such as the Roman sarissas.

Pikes today are used to carry the colours of an infantry regiment.