Selection of weeds with greater allelopathic potential can be used as a tool in sustainable crop production. The study aims at exploring the allelopathic effects of four weed species on seed germination of the test crop (O. sativa L). Four weed species used are namely, Cyperus esculentus (Della), Axonopus compressus (Itsit), Convulvulus arvensis (Lehli) and Parthenium hysterophorus (Parthenium). A laboratory experiment using completely randomized design was conducted on ten local and exotic varieties of O. sativa by using filter-paper bioassay technique. The crude extracts were prepared in ethanol solvents (10:100 w/v) and was further used in germination experiments. Ten days old rice seedlings (including A. compressus + C. arvensis and C. esculentus + P. hysterophorus) were observed after treatments with crude extracts of weed leaves. A comparative study of the seedlings was conducted with control sets treated with distilled water. Germination % age was observed at an interval of 24hr up to 8 days and expressed as % seed germination. The interaction between C. esculentus + P. hysterophorus indicated a significant effect on germination rate, plumule length, radicle length, fresh weight and dry weight of seeds. Results showed that allelopathic effects caused a significant increase among rice varieties: Munji 220 (96%), Sabina (84%) and Gulfmonth (80%). Conversely, the seedling growth of Basmati 370, CB-42, B. Pak and B. 802 rice varieties were least effected by weed extracts as compare to control. Pre sowing soaking by weed extracts proved to be the most effective to germination and seedling growth of rice. The overall results indicated the possible supportive effect of allelo-chemicals present in tested weeds on rice seeds.