| Nalla Thanni Theevu | |
| Native Name: | நல்ல தண்ணி தீவு |
| Area Km2: | 1.01 |
| Elevation M: | 11.9 |
| Country: | India |
| Country Admin Divisions Title: | State |
| Country Admin Divisions: | Tamil Nadu |
| Country Admin Divisions Title 1: | District |
| Country Admin Divisions 1: | Ramanathapuram |
| Country Admin Divisions Title 2: | Taluk |
| Country Admin Divisions 2: | Kadaladi taluk |
Nalla Thanni Theevu (Tamil: நல்ல தண்ணி தீவு ) is an island situated in the Gulf of Mannar about 4 kilometers south-east of the coast of Tamil Nadu, India. It is one of the three uninhabited islands in the Gulf of Mannar the others being Krusadai Island and Muyal Island.[1] It forms a part of the Kadaladi taluk of Ramanathapuram district.