Seagate Technology Holdings plc is an American data storage company. It was incorporated in 1978 as Shugart Technology and commenced business in 1979. Since 2010, the company has been incorporated in Dublin, Ireland, with operational headquarters in Fremont, California, United States.

Seagate developed the first 5.25-inch hard disk drive (HDD), the 5-megabyte ST-506, in 1980. They were a major supplier in the microcomputer market during the 1980s, especially after the introduction of the IBM XT in 1983. Much of their growth has come through their acquisition of competitors. In 1989, Seagate acquired Control Data Corporation's Imprimis division, the makers of CDC's HDD products. Seagate acquired Conner Peripherals in 1996, Maxtor in 2006, and Samsung's HDD business in 2011. Today, Seagate, along with its competitor Western Digital, dominates the HDD market.