Hiyō was the name ship of her class of two aircraft carriers of the Imperial Japanese Navy (IJN). Originally planned as the ocean liner Izumo Maru (出雲丸) in 1939, she was purchased by the Navy Ministry in 1941 for conversion to an aircraft carrier. Completed shortly after the Battle of Midway in June 1942, she participated in the Guadalcanal campaign, but missed the Battle of the Santa Cruz Islands in October because of an electrical generator fire.

The two Hiyō-class aircraft carriers were built for the Imperial Japanese Navy (IJN) during World War II. Both ships of the class, Hiyō and Jun'yō, were originally laid down as luxury passenger liners before being acquired by the IJN for conversion to aircraft carriers in 1941. Jun'yō was the first of the sister ships to be completed in May 1942 and the ship participated in the invasion of the Aleutian Islands the following month. Both ships participated in several battles during the Guadalcanal Campaign in late 1942. Their aircraft were disembarked several times and used from land bases in a number of battles in the South West Pacific.