Ben Stack (Scottish Gaelic: Beinn Stac) is a mountain in Sutherland, in the northwest of Scotland.

It is regarded as a moderately easy walk for walkers and hikers due to its overall height and its accessibility from the A838 road.

It is most commonly climbed from the southeast, following the long eastern ridge of Leathad na Stioma.

A slightly steeper alternative comes from the northwestern side, starting from near Lochstack Lodge.

On 6 August 2005 former U.K. Foreign Secretary Robin Cook died after collapsing with a heart attack whilst walking down from the summit.