WTOS-FM (105.1 MHz), known as "105 & 101 TOS", is a commercial mainstream rock radio station licensed to Skowhegan, Maine, whose studios are located in Augusta.

Transmitting from Sugarloaf Mountain, the signal covers a large swath of rural Maine as well as the cities of Augusta, Bangor and Lewiston, and portions of southern Quebec and northern New Hampshire.

WTOS-FM originated as a free-form rock music station in 1973 started by John Pineau on 107.1 MHz, with a studio based in Skowhegan, Maine.

After a public funeral through downtown Skowhegan for the previous format (organized by then-Music Director Duane Bruce), "The Mountain" continued to build up a large local following of fans, which was especially obvious at its frequent on-location remotes, usually at area bars and nightclubs.

In May 2008, WTOS and the 16 other Clear Channel stations in the Augusta and Bangor markets were sold to Blueberry Broadcasting, a Maine-based company headed by Louis Vitale and Bruce Biette.

The station is also heard by listeners in northern New Hampshire and parts of Vermont, although reception can be sporadic in those areas due to interference from the White Mountains.