Guiscriff (; ) is a commune in the Morbihan department in Brittany in north-western France.
Inhabitants of Guiscriff are called Guiscrivites. Guiscriff's population peaked at 5,896 in 1921 and declined to 2,037 in 2023. This represents a 65% decrease in total population since the peak census figure.
Historically, the village belongs to Cornouaille. The village centre is located north of Quimperlé and east of Quimper.