Siba () is a town in Luocheng Mulao Autonomous County, Guangxi, China. As of the 2019 census it had a population of 56,986 and an area of .
As of 2021, the town is divided into three communities and twenty-one villages:
Silu Township () was set up in 1925 during the Republic of China.
In 1952, it was renamed "Siba Township" (). Its name was changed to "Siba People's Commune" () in August 1958. It reverted to its former name of "Siba Township" in October 1984. In 1992 it was upgraded to a town. In August 2005, Xiali Township () was merged into the town.
The town is situated at the southwest of Luocheng Mulao Autonomous County, bordering Tianhe to the west, Yizhou District to the south, and Dongmen to the east and north.
The Longtan Reservoir () is located in the town, covering a total catchment area of and has a storage capacity of some of water.
The town experiences a subtropical monsoon climate, with an average annual temperature of , total annual rainfall of , a frost-free period of 320 days and annual average sunshine hours in 1402.5 hours.
The economy of the town is largest based on agriculture, including farming and pig-breeding. Significant crops include rice, corn, and soybean. Commercial crops include sugarcane, cassava, and tobacco.
The 2019 census showed the town's population to be 56,986, an increase of 2.0% from the 2011 census.
The town is rich in cultural traditions. It is also the hometown for many celebrities. The Former Residence of Wei Yiping () is a popular attraction in the town to commemorate Wei Yiping, a Communist martyr who died while crossing the Yangtze River in October 1945. The Birthplace of Liu Sanjie () is a well known tourist spot, named after Liu Sanjie, a legendary figure of Zhuang people in Guangxi.
The Provincial Highway S204 passes across the town.