The Mowag Piranha is a family of armoured fighting vehicles designed by the Swiss company Mowag (since 2010 General Dynamics European Land Systems – Mowag GmbH).

Five generations of vehicles have been produced, manufactured by Mowag or under licence by other companies such as the LAV, and variants are in service with military forces throughout the world.

Piranhas are available in 4×4, 6×6, 8×8, and 10×10 wheel versions. There are several variants within these versions, giving different degrees of armour protection and several kinds of turret, for use in a variety of roles. Piranha derivatives have been assigned roles as troop transports, command vehicles, fire support vehicles, tank trainers, and police vehicles.

Piranhas are used by the Swiss Army. Swiss-built Piranha derivatives have been exported to Ireland, Romania, Spain, and Belgium. The Romanian and Belgian armies have selected the Piranha IIIC 8×8. Belgium converted to an all-wheeled force, and replaced all their M113 armoured personnel carriers, AIFVs and Leopard 1 tanks with 268 Piranha IIIC in 7 variants.

Piranha derivatives have been manufactured under license by General Dynamics (Canada), BAE Systems Land Systems (UK), Cardoen and FAMAE (Chile), and in the USA.

A new Piranha V version, weighing between 25 and 30 tons, was announced as the provisional winner of the British Army's Future Rapid Effect System (FRES) program in May 2008, but this selection was reversed seven months later and bidding started again.^{[citation needed]}

General Dynamics European Land Systems launched their new Piranha Class 5 at Eurosatory 2010 on 15 June and it was reported that the British MoD were showing renewed interest, but struggling with budget constraints.

The MOWAG Piranha 4×4 IB was an armored personnel carrier.