A koncerz (Polish pronunciation: [ˈkɔn.t͡sɛʂ]) is a type of sword used by Polish-Lithuanian hussars in the Renaissance period. It is a narrow and long thrusting sword, generally used by a type of heavy cavalry (husaria, the famed Polish hussars) and optimized to defeat body armor (either by piercing directly through the metal links of mail armour, or by thrusting at the exposed gaps between the plates of plate armour), but was not used to cut or slash at enemy combatants.^[1]

The koncerz originated from a medieval sword and appeared at the end of the 15th century when it was about 1.3 metres (51 in) long, and relatively unwieldy compared to single-handed thrusting swords designed for use by infantry. By the late 16th century it had increased to 1.6 metres (63 in) in overall length, with a 1.4 metres (55 in) blade length, and optimized for weight distribution and balance. The koncerz was used more like a lance while mounted on horseback; it provided the rider with a very long reach in a relatively compact and portable format that was suitable to carry as a sidearm (the primary weapon of hussars was a kopia (very long lance)).^[1] As it was used primarily for thrusting, the koncerz often had no cutting edge, only a very sharp point; the blade itself was triangular or square in cross section in order to be more rigid.

The closest Western European equivalent is the long two-handed thrusting sword, known as an estoc, or 'tuck'.