© 2022 Pamukkale University. All Rights Reserved.The emergence of bacteria resistant to conventional antibiotics and the inability of these antibiotics to treat bacterial biofilm-induced infections cause millions of deaths every year. This situation has prompted scientists to develop alternative strategies to combat infectious diseases. Among these, researches on phytochemicals to reduce bacterial virulence in Pseudomonas aeruginosa have gained momentum in recent years. The main reasons behind this are the production of virulence factors and biofilm formation, all of which are under the control of quorum sensing (QS) system. Hence, inhibition of the QS pathways is an eligible strategy for the control of microbial pathogenesis. For the first time in the present study, the methanolic seed extract of avocado was evaluated for its anti-QS activity against P. aeruginosa PAO1. The results of the experiments carried out proved that the extract has inhibitory activity on the regulation of virulence and biofilm formation. Phytochemical analysis resulted in the identification of epicatechin, catechin, chlorogenic acid, caffeic acid, quercetin, kaempferol, vanillin, ferulic acid in the extract. Then, the mechanism of action for the extract was investigated through molecular docking. Docking outcomes demonstrated that the major components, catechin, epicatechin, chlorogenic acid, could bind to the receptors of QS competitively. Hence, the mode of action for the extract might be through the inhibition of the QS. Considering the computational analysis results and the literature, it is thought that the anti-QS activity of the extract prepared from avocado seeds may be related to the synergistic effect of the phytochemicals it contains.