Svend Foyn (July 9, 1809 – November 30, 1894) was a Norwegian whaling, shipping magnate and philanthropist. He pioneered revolutionary methods for hunting and processing whales. Svend Foyn introduced the modern harpoon cannon and brought whaling into a modern age. He is also recognized as a pioneer who introduced sealing to Vestfold County.

Svend Foyn was born in the neighborhood of Foynegården at Tønsberg in Vestfold county, Norway. He was the son of shipmaster Laurentius Foyn (1772–1813) and Benthe Marie Ager (1781–1842). Foyn was fatherless at four years of age and his mother came to characterize his upbringing. By age 11, Foyn sent to sea on the family ships. He took navigational exams in Kristiansand at age 19 and from 1833 he was a master sailor.^{[citation needed]}

His ship initially transported lumber from Sweden and Norway to European ports and returned with manufactured goods. Started in 1846, Foyn was on the expedition for seals and walrus. By the 1860s, he had a fleet of whaling ships. In 1863, he built the world's first steam-powered catcher. Within four years he experimented with whaling on the coast of Finnmark county.

Foyn was the first to hit the whale with grenade harpoon. Svend Foyn patented his grenade harpoon gun in 1870. He modified existing designs and utilized ideas developed by Erik Eriksen. It consisted of a cannon that fired a barbed explosive head harpoon. Aimed and fired, the harpoon barb would hook into the whale. A moment later an explosive charge in the head of the harpoon would inflict a mortal wound. Then the whale was retrieved by a winch. Once alongside the whaling vessel, the whale was pumped full of air to keep it afloat, as the whale was moved to the location of processing.

The whole process of whaling was changed drastically when Svend Foyn invented the exploding harpoon. By doing so, he removed much of the danger from whaling although it remained a very dangerous undertaking. His invention increased the efficiency by which whales could be captured and made it possible to hunt the larger and faster rorquals, the largest group of baleen whales.

Svend Foyn introduced mechanized, steam-powered catcher boats equipped with bow-chaser deck cannons and heavy-caliber harpoons that exploded on impact. Foyn constructed his 86-ton, seven-knot Spes et Fides, the first steam-powered whale catcher. The ship was equipped with seven whale guns separately mounted on the forecastle, each firing a harpoon and grenade. The vessel was 94 feet (29 m) long, with a 20-horsepower (15-kW) engine. It could reach a speed of 7 knots (13 km/h).

With this development, he launched Norway into a new and profitable industry. After years of perfecting a cannon that could fire a grenade and harpoon simultaneously, Foyn finally managed to catch 30 whales in 1868. These increased efficiency and volume, enabling the harvest not only of all of the species that had been hunted for, but also the largest species which had eluded all previous hunting technologies. The whaling industry was in decline when Foyn first began his development of the bow-mounted harpoon cannon. Foyn's eventual successful development of the cannon, in combination with fast and sleek steam-powered catcher vessels, ushered in a modern whaling industry that was to become dominated first by the Norwegians, then the British and finally the Russians and Japanese.

The Antarctic Expedition of 1894–95 was funded by Svend Foyn and led by Henrik Johan Bull. The two-year expedition was a whaling expedition that sailed to the Ross Sea aboard the ship Antarctic. The crew included Carsten Borchgrevink, who later led the Southern Cross Expedition to Antarctica.