Echinochloa crus-galli (L.) Beauv is the most frequently reported troublesome weed in rice fields as it is aggressive, difficult to control and reduces rice yields significantly. An experiment was conducted during 2021 with an objective to assess the allelopathic effect of ten trees’ leaves aqueous extracts on the seed germination and seedling growth of E. cruss-galli. Leaves of ten tree species were separately dried and the aqueous extracts of each of them were diluted to obtain the three concentrations i.e. 5, 10 and 15% of each. Three concentrates of each of the tree leaves extract were used as treatments. The 15% concentration of the leaves extracts of all tree species exhibited highest efficacy in reducing germination and growth of E. crus-galli. Amongst all tree species studied, Aegle marmelos (L.) Corrêa tree leaves aqueous extract, at all concentrations caused greater allelopathic effect and maximum seedling root and shoot inhibition with lowest vigour index and seedling weight of E. crus-galli.