HD may refer to:

• 1 Science and technology
• 2 People
• 3 Academia
• 4 Business
• 5 Medicine
• 6 Places
• 7 Other

• High-definition, in reference to high-definition video, high-definition television (HDTV), Intel High Definition Audio, or HD Voice
• Hard drive, a computer device which stores digitally encoded data, also known as HDD
• Henry Draper Catalogue, an astronomical catalogue often used to designate stars
• High density, in reference to a floppy disk, other magnetic media or the optical formats HD DVD and Blu-ray
• Homeopathic Doctor, a doctor whom practices homeopathy, also known as HD
• Hybrid drive, a type of notebook computer hard drive that utilizes a large buffer
• Hydrogen deuteride, a diatomic compound of hydrogen and deuterium
• HD Radio, an abbreviation from the term Hybrid Digital/analog radio
• HD Photo, an image format
• the chemical warfare agent sulfur mustard, which in its distilled form is referred to as HD
• Hyperdeformation, extremely deformed atomic nuclei.