HHD may refer to:
Biology and medicine ATP2C1, a human enzyme Hailey–Hailey disease, a genetic disorder Hiatus hernia diafragmatica, a medical condition Home hemodialysis, for treating kidney failure
Other Astro Hua Hee Dai, a Malaysian television channel Hao Haidong (born 1970), Chinese footballer Headquarters and Headquarters Detachment in the United States Army Helena Historic District (disambiguation), various places in the United States High Holy Days (band), a Canadian rock band Hogshead (abbreviation: hhd), a barrel of liquid Holyhead railway station, in Wales Hybrid hard drive, a type of hard disk drive