The effect of lipophilic leaf and stem extracts from Aglaiaelaeagnoidea (A. Juss.) Benth. on seed germination and seedling growth were investigated with two weeds and two cultivated plants i.e. giant mimosa (Mimosa pigra L.), mung bean (Vigna radiata (L.) R. Wilczek), sandbur (Cenchrus brownii Roem. & Schult.)and rice (Oryza sativa L. cv. Khao Dawk Mali 105). Four concentrations of the extracts 0.5, 1.0, 5.0 and 10.0 mg/ml were used together with ethanol as a control. All concentrations of leaf extract showed no effect on seed germination of giant mimosa, but at the concentration 5.0 mg/ml could inhibit seed germination of sandbur and rice, and 10.0 mg/ml for mung bean. The concentrations 0.5, 1.0, 1.0 and 5.0 mg/ml could inhibit shoot length of sandbur, giant mimosa, mung bean and rice, respectively. The concentration 0.5 mg/ml could inhibit root length of giant mimosa, sandbur and rice, and 5.0 mg/ml for mung bean. Stem extract showed no effect on seed germination of giant mimosa and mung bean, the concentration 0.5 mg/ml could in hibit seed germination of sandbur and rice, inhibit shoot and root length of all testing plants. Stem extract inhibited seed germination of sandbur at lower concentration than leaf extract.Thus, the A. elaeagnoidea stem extract has potential to be source of bioactive compounds which may be developed for weed control instead of chemicals.