Grand Teton National Park is a national park of the United States in northwestern Wyoming. At approximately 310,000 acres (1,300 km2), the park includes the major peaks of the 40-mile-long (64 km) Teton Range as well as most of the northern sections of the valley known as Jackson Hole. Grand Teton National Park is only 10 miles (16 km) south of Yellowstone National Park, to which it is connected by the National Park Service–managed John D. Rockefeller Jr. Memorial Parkway. Along with surrounding national forests, these three protected areas constitute the almost 18-million-acre (73,000-square-kilometer) Greater Yellowstone Ecosystem, one of the world's largest intact mid-latitude temperate ecosystems.

Efforts to preserve the region as a national park began in the late 19th century, and in 1929 Grand Teton National Park was established, protecting the Teton Range's major peaks. The valley of Jackson Hole remained in private ownership until the 1930s when conservationists led by John D. Rockefeller Jr. began purchasing land in Jackson Hole to be added to the existing national park. Against public opinion and with repeated Congressional efforts to repeal the measures, much of Jackson Hole was set aside for protection as Jackson Hole National Monument in 1943. The monument was abolished in 1950 and most of the monument land was added to Grand Teton National Park.