The Transantarctic Mountains (85º00´S 175º00´W) are a mountain range in Antarctica which extend with some interruptions between Cape Adare and Coats Land, these mountains serving as the division between East Antarctica and West Antarctica. Included are the continuous but separately named mountain groups along the west side of the Ross Sea and the western and southern sides of Ross Ice Shelf; also the Horlick Mountains, the Thiel Mountains, Pensacola Mountains, Shackleton Range and Theron Mountains.

This purely descriptive name was recommended by the US-ACAN in 1962 and has since gained international acceptance.