Pitcairn House is a ruined 17th century laird's house, located in the modern Collydean residential area of Glenrothes, in Fife, Scotland. The ruins are approximately 15 x 5.5m, with the east gable rising to 6m. The rest of the building has collapsed to the foundations. It is thought that the building was up to three storeys high.
The site was excavated by archaeologists in 1980. A number of finds are now in the Kirkcaldy Museum. A steading and cottages were once associated with the house, although these were demolished when the housing estate was built.
Pitcairn House was not, as is sometimes reported, built by the Picts, a people whose culture disappeared from Scotland around the 10th century. The name Pitcairn does, however, have roots in the Pictish language, combining the common prefix pit, meaning a portion of land or farm, with the Gaelic cairn.
Some people argue that the ruins are very dangerous, but their historical significance has led to the designation of the ruin as a Scheduled Ancient Monument.