HH5, HH-5, HH 5, HH.5, may refer to:
- HH5, one of the Hamburger–Hamilton stages in chick development
- HH5, a model in the series of Honda Acty trucks
- Flag in Exile (novel), abbreviated "HH5", fifth main-line novel in the Honor Harrington novel series, part of the Honorverse fictional milieu created by David Weber
- CHD7, also known as HH5, the chromodomain-helicase-DNA-binding protein 7