Forglen House is a mansion house that forms the centrepiece of the Forglen estate in the parish of Forglen, north-west of Turriff, Aberdeenshire, in the north-east of Scotland. The lands were given to the abbots of the Abbey of Arbroath by King William the Lion before 1211 and the Monymusk Reliquary was held there. The original castle, built around 1346, was replaced by a vernacular harled house that was later extended. Significant development of the estate began when it was acquired by the family of Lord Banff and they started the work of landscaping and planting trees. It became their main family seat during the 18th century. After the death of William Ogilvy, the eighth and final Lord Banff, the estate passed by marriage to the Abercromby baronets who continued to enhance the property and maintained it as their main residence. Sir Robert Abercromby, 5th Baronet commissioned the Aberdeen City Architect, John Smith to design the present house in 1839.
Forglen House was sold by the Abercromby family in 1974 but remains in private ownership. It is not open to the public, although access to the grounds is available and some cottages can be hired as holiday lets, including one of the lodge houses.
The mansion is a Category A listed building and several other structures within the estate, including the stables and a Gothic-style mausoleum, are Category B listed. The gardens are listed on the Inventory of Gardens and Designed Landscapes in Scotland as outstanding in most sections.