| Ryōtsu | |
| Native Name Lang: | ja |
| Settlement Type: | Former municipality |
| Pushpin Map Caption: | Location in Japan |
| Subdivision Type: | Country |
| Subdivision Name: | Japan |
| Subdivision Type1: | Region |
| Subdivision Name1: | Hokuriku |
| Subdivision Type2: | Prefecture |
| Subdivision Name2: | Niigata Prefecture |
| Subdivision Type3: | District |
| Subdivision Name3: | Sado District |
| Extinct Title: | Merged |
| Extinct Date: | March 1, 2004 (now part of Sado) |
| Leader Title: | Mayor |
| Leader Title1: | Vice Mayor |
| Unit Pref: | Metric |
| Area Total Km2: | 233.37 |
| Population Total: | 16,710 |
| Population As Of: | 2003 |
| Timezone1: | JST |
| Utc Offset1: | +09:00 |
| Blank Name Sec1: | City hall address |
| Blank Name Sec2: | Climate |
| Blank Info Sec2: | Cfa |
was a city located in Sado Island, Niigata Prefecture, Japan.
On March 1, 2004, Ryōtsu and the other 9 municipalities in the island were merged to create the city of Sado. Since then, Ryōtsu has been one of the 10 subdivisions of Sado City.
As of 2003, the city had an estimated population of 16,710 and a density of 71.60 persons per km2. The total area was 233.37 km2.
The city was founded on November 3, 1954.
On March 1, 2004, Ryōtsu, along with the rest of Sado Island (the towns of Aikawa, Kanai, Sawata, Hatano, Mano, Hamochi and Ogi, and the villages of Niibo and Akadomari (all from Sado District)), was merged to create the city of Sado.