HH12, HH-12, HH 12, HH.12, may refer to:

Mission of Honor (novel), abbreviated "HH12", 12th main-line novel in the Honor Harrington novel series, part of the Honorverse fictional milieu created by David Weber

HH12, one of the Hamburger–Hamilton stages in chick development Gonadotropin-releasing hormone (HH12)

See also

HH (disambiguation) H12 (disambiguation) H (disambiguation)