The inhibition of acetylcholinesterase plays a vital role in the treatment of Alzheimer disease. This study aimed to explore the acetylcholinesterase inhibition potential of Phyllanthus amarus and its phytoconstituents through an in vitro and in silico approach. The in vitro acetylcholinesterase inhibitory activity of P amarus was carried out, followed by the molecular docking studies of its phytoconstituents. The top-ranked molecules identified through molecular docking were subjected to molecular dynamics simulation (MDS) and density functional theory (DFT) studies. The results obtained revealed the methanolic extract of P amarus as a potent acetylcholinesterase inhibitor, while amarosterol A, hinokinin, β-sitosterol, stigmasterol and ellagic acid were identified as potential acetylcholinesterase inhibitors. The MDS and DFT results are in agreement with those obtained from the docking studies. Our findings suggest further studies on the hit molecules.