Silseong of Silla (died 417) (r. 402–417), whose name is also given as Silju or Silgeum, was the 18th ruler of the Korean kingdom of Silla. He was the son of the general (gakgan) Kim Daeseoji, who was the younger brother of King Michu. His title is given as Maripgan in the Samguk Yusa, and as Isageum in the Samguk Sagi.
As a child in 392, Silseong was sent to Goguryeo as a hostage. He did not return to Silla until 401. In the following year, the reigning King Naemul died. Because Naemul's sons were still young, the nobles of the kingdom placed Silseong on the throne.
After being crowned in 402, Silseong established an alliance with Wa and sent Naemul's son Kim Misaheun there as a hostage. In 412, he sent another son of Naemul, Kim Bokho, to Goguryeo as a hostage. He tried to kill another possible heir, Kim Nulji, but ended up dying himself.