| Sio | |
| Pushpin Map: | Papua New Guinea |
| Coordinates: | -5.9551°N 147.3704°W |
| Pushpin Label Position: | right |
| Pushpin Map Caption: | Location within Papua New Guinea |
| Subdivision Type: | Country |
| Subdivision Name: | Papua New Guinea |
| Subdivision Type1: | Province |
| Subdivision Name1: | Morobe Province |
| Population Density Km2: | auto |
| Demographics Type1: | Languages |
| Demographics1 Title1: | Main languages |
| Demographics1 Info1: | Tok Pisin, English |
| Timezone1: | AEST |
| Utc Offset1: | +10 |
Sio is a town on the north coast of Huon Peninsula, Papua New Guinea. It is located in Wasu Rural LLG, Morobe Province.
A Lutheran mission station was established at Sio in 1910.
The town was occupied by Imperial Japanese forces during World War II and was a major operating base. During the Huon Peninsula campaign the town was wrestled from the defending elements of the Japanese 20th Division by the Australian 9th Division and the Papuan Infantry Battalion, during the Battle of Sio, fought between December 1943 and January 1944.