Allelopathy plays a vital role both in natural and managed ecosystems.Eventhough allelopathy includes both positive and negative effects of one plant on the other,most of the studies seems to focus only on its deleterious impacts alone. Tectona grandis(Teak) is the most valuable timber of the world and indigenous to Burma,India and Thailand under social forest scheme.Also introduced in Thanjavoor district on the banks of rivers,streams and ponds. This experiment was conducted in order to evaluate the allelopathic effects of the aqueous extract (A.E.) of Tectona grandis Linn.f. on the seedling growth in Vigna mungo(Black gram) and Vigna radiata (Green gram) . For this present study the seeds of Vigna mungo (Black gram)Var.ADT-3. and Vigna radiata(Green gram)Var.Co.3.were selected. Dried fallen leaves were collected from coastle area of Cuddalore District.The sterilized fifty seeds were placed in petridishes containing different concentrations of teak leaf extract(0,5,10,25,50,75 and100%).The dry weight of both crops Vigna mungo and Vigna radiata were increased in 5% concentrated treatment. All other concentrations showed a decreased dry weight and very low dry weight were observed in 100% treated seedlings. Results showed that low concentrations of T.grandis dry leaves Allelopathic Effect( A.E.) had significant promotary effect on the Black gram and Green gram seedlings growth.The higher applied concentration from aqueous extracts of T.grandis was completely inhibited Vigna mungo and Vigna radiata seedling seedling growth by 100%, at 50 g compared to its control. However, treatments with higher concentrations had negative effects on rate of seedling growth. Low concentration increase the seedling growth increase in both crop seedlings shows promontory effect. As the concentration of T.grandis extract increased seedling growth of black gram and green gram decrease shows inhibitory effect.