HH15

HH15, HH-15, HH 15, HH.15, may refer to:


 * Toll of Honor (novel), abbreviated "HH15", 15th main-line novel in the Honor Harrington novel series, part of the Honorverse fictional milieu created by David Weber


 * HH15, one of the Hamburger–Hamilton stages in chick development
 * Strain Hh15, the type strain for Cryobacterium luteum (C. luteum) bacteria