Hm3

HM3 can refer to:
 * Hannah Montana 3, a soundtrack for the Hannah Montana TV series
 * United States Navy Hospital Corpsman, Third Class (E-4)
 * A Human Genome Organisation symbol for muscarinic acetylcholine receptor M3
 * One of the implementations of Modula-3
 * Horological Machine No.3, a timepiece from MB&F

hm³ can refer to:
 * Cubic hectometre