The Hag's Tooth (Irish: Stumpa an tSaimh, meaning 'stump of the sorrel'),[1] at 650 metres (2,130 ft) high, is a sharp rock spike which is the 193rd highest peak in Ireland on the Vandeleur-Lynam scale.

The Hag's Tooth is a distinctive triangular rock feature encountered when walking through the Hag's Glen on the way to climbing Carrauntoohil 1,038.6 metres (3,407 ft), Ireland's highest mountain, via the classic Devil's Ladder route.

[5] The Hag's Tooth does not appear in the MountainViews Online Database, 100 Highest Irish Mountains, as the prominence threshold is 100 m (328 ft).

[9] The narrow rocky ridge from the Hag's Tooth up to the summit of Beenkeragh, the Hag's Tooth Ridge, is regarded for its scrambling, and for its views into the Eagle's Nest area and the major gullies of Carrauntoohil's north-east face.

[10] The route also enables loop to be completed by continuing across the infamous Beenkeragh Ridge to Carrauntoohil, and then descending via the Heavenly Gates, back into the Hag's Glen.