Ji Fa

King Wu of Zhou 周武王
King Wu painted by Ma Lin
King of China
Reign	1046–1043 BC
Predecessor	King Zhou of Shang
Successor	King Cheng of Zhou
Died	1043 BC
Spouse	Yi Jiang (邑姜), daughter of Jiang Ziya
Issue	King Cheng of Zhou
Full name Ancestral name: Jī (姬) Given name: Fā (發)
House	Zhou dynasty
Father	King Wen of Zhou
Mother	Tai Si

King Wu of Zhou (Chinese: 周武王; pinyin: Zhōu Wǔ Wáng) was the first king of the Zhou dynasty of ancient China. The chronology of his reign is disputed but is generally thought to have begun around 1046 BC and ended three years later in 1043 BC.

King Wu's ancestral name was Ji () and given name Fa (). He was the second son of King Wen of Zhou and Queen Tai Si. In most accounts, his older brother Bo Yikao was said to have predeceased his father, typically at the hands of King Zhou, the last king of the Shang dynasty; in the Book of Rites, however, it is assumed that his inheritance represented an older tradition among the Zhou of passing over the eldest son. (Fa's grandfather Jili had likewise inherited Zhou despite two older brothers.)

Upon his succession, Fa worked with his father-in-law Jiang Ziya to accomplish his father's unfinished task: overthrowing the Shang dynasty. In 1048 BC, Fa marched down the Yellow River to the Mengjin ford and met with more than 800 dukes. He constructed an ancestral tablet naming his father Chang King Wen and placed it on a chariot in the middle of the host; considering the timing unpropitious, though, he did not yet attack Shang. In 1046 BC, King Wu took advantage of Shang disunity to launch an attack along with many neighboring dukes. The Battle of Muye destroyed Shang's forces and King Zhou of Shang set his palace on fire, dying within.