Schinus areira L., commonly known as "Aguaribay" or "Molle", belongs to the family Anacardiaceae. This plant from the southwest of the province of Buenos Aires, Argentina, is used in traditional medicine, and known for several important biological actions. Butyrylcholinesterase (BChE) may represent an important therapeutic target for Alzheimer Disease (AD), and the search for new dual AChE (acetylcholinesterase) and BChE inhibitors is mandatory to find new alternative treatments for AD patients that do not respond to selective AChE inhibitors. The aim of this work is to evaluate the inhibition of cholinesterase enzymes by the essential oil of Schinus areira. The chemical composition of the essential oil (EO) obtained from the aerial parts by hydrodistillation was determined by gas chromatography-mass spectrometry (GC-MS). AChE and BChE inhibition were determined spectrophotometrically by Ellman’s method. A bioguided fractionation of the EO was performed using different chromatographic techniques (preparative and thin layer chromatography, silica gel column chromatography) to achieve the isolation of the active components. The EO, containing α-phellandrene, camphene, α-pinene and β-eudesmol as major components, showed more effective BChE inhibition (IC₅₀ = 42.37 µg/mL) compared to AChE inhibition (IC₅₀ = 347.3 µg/mL). The isolated compounds β-eudesmol and α-phellandrene showed potent BChE inhibition (IC₅₀ = 11.6 - 19.8 µM) and moderate AChE inhibitory activity (IC₅₀ = 65.63 – 84.54 µM). These results suggest that the EO of S. areira could be a source of bioactive compounds that may be of interest for the development of potential new alternatives in the treatment of AD