Juliana Young Koo, born Yen Yu-yun (Chinese: 嚴幼韻; September 26, 1905 – May 24, 2017), was a Chinese-American diplomat and supercentenarian who worked in the UN Protocol Department.

[1] Her first husband, Chinese diplomat Clarence Kuangson Young, was assassinated by Japanese imperial forces during World War II.

Koo was born on September 26, 1905 into a wealthy family with business and government ties in Tianjin, China as Yen Yu-yün (or Yan Youyun).

[citation needed] At university, a special car took her to campus and brought her back, since its number was 84, the male students nicknamed her "Miss 84".

[3] She married Clarence Kuangson Young Chinese: 楊光泩; pinyin: Yáng Guāngshēng; Wade–Giles: Yang Kuang-sheng) on September 6, 1929.

Young was arrested by the Japanese during World War II and executed on April 17, 1942 together with seven consulate staff.

[6][7] Shirley Young (1935–2020) was a prominent business executive for Grey Advertising and General Motors.