Seong of Baekje (also Holy King, died 554) (r. 523–554) is the 26th king of Baekje, one of the Three Kingdoms of Korea.
He is a son of Muryeong of Baekje and is best known for making Buddhism the state religion, moving the national capital to Sabi (present-day Buyeo County), and reclaiming the center of the Korean Peninsula.
His demise eventually comes at the hands of an ally who betrays him.