William Charles Achi Jr. (July 1, 1889 – June 17, 1947) was a Hawaiian attorney and territorial judge, as well as composer.

[1] On November 19, 1919, Achi was appointed to a four-year term as judge of the Fifth Circuit Court of the Territory of Hawaii by President Woodrow Wilson.

[3] The replacement was motivated, at least in part, by an internal feud between territorial delegate Lincoln L. McCandless and Achi's close friend, Honolulu mayor John H.

[3] Achi married Rebecca Kaulani Kruce at Kainaliu in the Kona District of the island of Hawaii, on June 7, 1911.

[4] They had six children: William Charles III, Richard Kelii, Mary Ann, Rebecca Kaohuleilani, Lincoln Leleiwi, and Stanley Alapai.