The study assessed the allelopathic potential of C. odorata aqueous leaf extract on seed germination and seedling growth of crops selected maize and beans (yellow and red), cowpea and finger millet, and pasture species Clitoria ternatea and Macroptilium lathyroides. Leaf extract concentrations of 0, 25, 50, 75 and 100% were prepared and experiments set in three replicates under completely randomized design. Data on seed germination were collected daily, but shoot and root length were measured on 10th day of the experiment. Germination Index (GI), Rate of germination (RG), Germination percentage (GP), Inhibitory percentage (IP), Seedling Vigor Index (SVI), relative elongation ratio of shoot (RERS) and relative elongation ratio of root (RERR) and were calibrated. C. odorata leaves extract significantly effected (p < 0.05) GI, GP, SVI and IP for all crops and pasture. The GI and GP reduced with increased concentration on selected species. Nevertheless, cowpea, finger millet and Clitoria ternatea, were much affected compared with other species. At 100 %, RERRS and SVI for finger millet, Yellow maize, Red maize, Cowpea, red beans, Yellow beans, Clitoria ternatea and Macroptilium lathyroides were 68.39, 53.92, 71.43, 3.18, 14.82, 5.90, 34.44 and 200.21, 338.43, 273.82, 0.47, 421.84, 344.53, 14.41, 42.35. The SVI, RERR and RERS were highly impacted at concentration ≥ 75% though GP, GI, and RG were inhibited at 100%. Generally, C. odorata leaf extract inhibits seed germination and seedling growth of selected crop and pasture species. Further study suggestions are on inhibitory mechanisms involved and allelopathic behaviour under field conditions.