Harthill Castle is a large 17th-century Z-plan castle, about 5.5 miles (9 km) west-north-west of Inverurie, Aberdeenshire, Scotland, south of Kirkton of Oyne,[1] at grid reference NJ687252.

The Leith family held the property from 1531, and they probably built the currently standing castle: dates of 1601 or 1638 are disputed.

The last Leith of Harthill is believed to have set the castle on fire deliberately.

The hall, which was a fine chamber, had stone seats and a large fireplace.

Spiral staircases in the thickness of the walls led to private chambers above and in the towers.