| Surname: | Ryūzōji clan |
| Surname Nihongo: | 龍造寺 |
| Image Size: | 140px |
| Image Caption: | The emblem (mon) of the Ryūzōji clan |
| Home Province: | Hizen |
| Parent House: | Fujiwara clan |
| Titles: | Daimyo |
| Founder: | Fujiwara no Suie |
| Final Ruler: | Ryūzōji Masaie |
| Founding Year: | 1186 |
| Dissolution: | 1607 |
| Ruled Until: | 1607, death of Ryūzōji Masaie |
was a Japanese kin group which traces its origin to Hizen Province on the island of Kyushu.[1]
The clan was founded by Fujiwara no Suekiyo in 1186.[2] The clan was allied with Ashikaga Takauji in 1336, but they were defeated in fighting with the Ōtomo clan to the east and Shimazu clan to the south.[1]
Ryūzōji Takanobu is known for expanding his clan's holdings. He took land from the Shōni clan.[2] Ryūzōji Masaie (1556–1607) was the son of Takanobu. In 1587, Masaie joined the forces of Toyotomi Hideyoshi against the Shimazu clan. In the same year, he was confirmed as head of the Saga Domain (350,000 koku), but control of the domain passed to Nabeshima Naoshige[3] when Masaie was killed in battle.[1]