| Conflict: | Siege of Gaeta |
| Partof: | the Neapolitan War |
| Date: | 28 May – 8 August 1815 |
| Place: | Gaeta, present-day Italy |
| Coordinates: | 41.2167°N 13.5667°W |
| Result: | Coalition victory |
| Combatant1: | |
| Commander1: | Joseph Freiherr von Lauer |
| Commander2: | Maresciallo di Campo Alessandro Begani |
| Strength1: | 2,500 |
| Strength2: | 2,000 |
| Casualties1: | 277 killed or wounded |
| Casualties2: | 238 killed 1,762 captured |
| Map Type: | Europe |
| Map Relief: | 1 |
| Map Size: | 300 |
The siege of Gaeta of 1815 was a three-month siege of the city of Gaeta by Austrian forces during the Neapolitan War.
The Neapolitan garrison was commanded by Maresciallo di Campo Alessandro Begani, general of the deposed King of Naples Gioacchino Murat, while the Austrians were commanded by Joseph Freiherr von Lauer. The Austrians were reinforced by the ships of the Royal Navy. On 8 August 1815 the city capitulated, marking the official end of the war.
The defenders were forced to capitulate due to the lack of food and for the diseases that raged in the troops. For the surrender, General Begani obtained honorable conditions.