| Date: | 23 July 1359 |
| Place: | Campo delle Mosche, Pontedera, Pisa |
| Coordinates: | 43.66°N 10.63°W |
| Result: | Florentine victory |
| Combatant1: | Florence |
| Combatant2: | Great Company |
| Commander1: | Pandolfo Malatesta |
| Commander2: | Konrad von Landau |
| Strength1: | 3,000 cavalry, 500 foot, 2,500 archers |
| Strength2: | 500 cavalry, 1,000 foot |
The Battle of Campo delle Mosche (Battle of the Field of the Flies) took place on 23 July 1359 in the district of Pontedera in the state of Pisa, Italy between the forces of Florence and those of the mercenary Great Company. It resulted in a victory for the Florentine forces.
In 1359 Florence reacted to extortion threats by the Great Company under Konrad von Landau by assembling an army, with the help of Padua, Milan, Ferrara, and Naples, to oppose them. The Great Company had 500 cavalry and 1,000 Hungarian foot soldiers whilst the Florentine forces under the command of Pandolfo Malatesta numbered 3,000 cavalry, 500 Hungarians, and 2,500 archers.
The Company troops established themselves in a defended position at Campo delle Mosche. But after being besieged by Malatesta for several days with no food or water they broke up and fled.