| Conflict: | Siege of Mitsuji |
| Partof: | the Sengoku period |
| Date: | May 1576 |
| Place: | Mitsu-ji, Osaka |
| Map Type: | Japan Osaka Prefecture#Japan |
| Map Relief: | yes |
| Result: | Ikkō-ikki victory |
| Combatant1: | Ikkō-ikki monks |
| Combatant2: | forces of Oda Nobunaga |
| Commander1: | Various/Unknown |
| Commander2: | Oda Nobunaga Harada Naomasa Niwa Nagahide Hashiba Hideyoshi Takigawa Kazumasu Inaba Ittetsu Hachiya Yoritaka |
| Strength1: | 15,000 sōhei |
| Strength2: | 3,000 ashigaru |
The 1576 siege of Mitsuji (Japanese: 三津寺砦の戦い) was part of the eleven-year Ishiyama Hongan-ji War. The Ikkō-ikki, a group of warrior monks and peasants, controlled the fortress and stood as one of the primary obstacles to Oda Nobunaga's bid for power.
In May 1576, Nobunaga personally took part in an attack on the fortress. He led a number of ashigaru (foot soldiers) in pushing back the Ikki garrison to their inner gates. Nobunaga suffered a bullet wound to his leg.[1] However, Nobunaga lost one of his generals, Harada Naomasa.