ALLELOPATHY has become a much more important phenomenon in biological control method of weeds in any kind of agricultural practices. So, the present study has been carried out to evaluate the allelopathic influence of the Lupinus leaf extract on biochemical constituents and enzymatic activities of the Portulaca oleracea L. plant. The obtained results indicate that induction of calmodulin (CaM), abscisic acid (ABA) and indole acetic acid (IAA) levels in the P. oleracea plant under the effect of Lupinus leaf extract. Also, seed germination, total soluble sugars, total lipids, total amino acids and total protein contents were reduced in P. oleracea under treatment with Lupinus leaf extract. The extract induced the activities of both α-amylase and IAA oxidase but inhibited the activities of nitrate reductase (EC, 1.7.1.3), glutamine synthetase (EC, 6.3.1.2) and pyruvate dehydrogenase (EC, 1.2.4.1). Thus, allelopathic extract of the L. termis may be used as eco-friendly natural herbicide for management of the P. oleracea.