William Owen Smith (August 4, 1848 – April 13, 1929) was a lawyer from a family of American missionaries who participated in the overthrow of the Kingdom of Hawaii.

[1] His parents were in the tenth set of missionaries to Hawaii from the American Board of Commissioners for Foreign Missions who arrived in 1842.

[2] His sister Charlotte Elizabeth "Lottie" Smith (1845–1896) married Alfred Stedman Hartwell (1836–1912), who was a former general in the American Civil War, on January 10, 1872.

While working at the Lāhainā Courthouse, on April 24, 1873, he planted a banyan tree (Ficus benghalensis) to commemorate the 50th anniversary of the arrival of Christian missionaries on the island.

He acted as deputy attorney general, and was elected as a representative from Maui to the legislature of the Hawaiian Kingdom from 1878 to 1884.

On January 17, he was appointed to the executive council (the new cabinet) of the Provisional Government of Hawaii under president Sanford B. Dole, the son of his former teacher.

A native Hawaiian suspect, Kapea Kaʻahea, was arrested, tried on November 13, 1897, and found guilty of murder in the first degree.

The rushed nature of the prosecution was thought to be an attempt to show the United States that the government was in firm control.

[11] In August 1898, Smith offered to resign, but although now annexed, the old republic government continued to operate.

[14] On March 20, 1899, he was replaced as attorney general by Henry Ernest Cooper and returned to private practice.

Despite his role in the overthrow, deposed Queen Liliʻuokalani selected him to be a founding trustee of her own estate when she made her will in December 1909.

[17] On November 30, 1915, Prince Jonah Kūhiō Kalanianaʻole challenged the will in court, saying she was "of weakened mind" under the influence of the trustees.

His other daughter, Anna Katherine Smith (1888–1960), married Harry's brother Samuel Alexander Baldwin (1885–1950) and lived on Maui.

His ties to the oligarchy known as the "Big Five" that dominated the island economy led the opposition press to call him "King Bill the First".

Other notable members of the firm through the years included Cyrus Nils Tavares, Alan Cooke Kay, and W. F.L.