South Teton, Mountain peak in Grand Teton National Park, Wyoming, USA.

South Teton is a 12,519-foot (3,816 m) summit in the Cathedral Group of the Teton Range, fifth-highest peak in the range and in Grand Teton National Park, Wyoming. It stands south of Middle Teton, west of Cloudveil Dome and Nez Perce Peak, and north of Mount Wister, between Garnet Canyon and Avalanche Canyon with Lake Taminah and the Shoshoko Falls. It forms the highest point of the ridge running west from Shadow Peak, and repeated glaciation shaped its present form.

The first ascent was made on August 29, 1923, by Albert R. Ellingwood and Eleanor Davis via the Northwest Couloir (Class 4). Ellingwood also made the first ascent of Middle Teton the same day. Davis was the first woman to ascend Grand Teton. On July 19, 1959, Yvon Chouinard and William Mason climbed the North Face (Class 5.6).

French trappers of the Hudson's Bay Company named Grand Teton, Middle Teton and South Teton in the 1800s, calling them Les Trois Tetons, "the three breasts". The Shoshone, Native Americans of the region, knew the peaks as the Hoary Headed Fathers.

Most ascents start at Lupine Meadows Trailhead south of Jenny Lake, following Garnet Canyon to the saddle between South and Middle Teton at about 9,200 feet (2,800 m). From that pass most parties continue to the summit. The climb is long, so good fitness matters; the Northwest Couloir first-ascent route is rated Class 4, while the North Face reaches 5.6.

The peak can be approached via three distinct climbing routes: the Northwest Couloir, West Ridge, and North Face, each presenting different technical demands. The Northwest Couloir is the most popular route, yet it still requires rock climbing and careful snow navigation through narrow passages.