Allelopathic effect of seven tree leaf extracts viz., Azadirachta indica, acacia arabica, Eucalyptus tereticornis, Tamarindus indica, Tectona gradis, Samanea saman and Syzygium cumini each at 5 and 10 per cent concentration was tried on seed germination, vigour index, seedling length and seedling dry matter of sorghum and rice. The study revealed a differential response on these parameters. All the tested leaf extracts were found to promote germination in sorghum while A. indica and A. arabica increased germination in rice. Concentrations of leaf extracts also found to exhibit differential response on various parameters and so also the interaction effect between leaf extracts and concentrations.