HD

HD may refer to:

• Hilda Doolittle, also known as H.D., American poet
• High definition television, HD-DVD, high definition media formats
• Hard disk, or hard drive, a type of computer storage hardware (also HDD for hard disk drive)
• Hybrid drive, a type of notebook hard drive that utilizes a large buffer
• Harley-Davidson NYSE: HDI, an iconic American motorcycle manufacturer
• Home Depot NYSE: HD, a chain of home improvement warehouse retailers
• Attention-deficit hyperactivity disorder, known as Hyperactivity Disorder (HD), as in AD/HD
• High Density, in reference to a floppy disk or other magnetic media
• Higher Diploma, an academic award.
• Henry Draper Catalogue, a sequential numbering system for stars ordered by right ascension
• Hodgkin's disease
• Huntington's disease
• Hormone disruptor
• Mustard gas