A study was conducted to evaluate the allelopathic effect of leaf aqueous extract of teak (Tectona grandis) on rice (Oryza sativa) seeds under laboratory conditions. The leaf aqueous extract showed significant inhibitory effect on germination and other growth parameters of rice. The inhibitory effect was proportional to the concentrations of the extract and the higher concentration had the higher inhibitory effect. Thus teak seems to be a potential threat to the cereals industry under small-scale farming condition. Therefore, it can be recommend that different remedial practices (like removal of excess leaf litter) should be done before sowing rice in the land previously planted with teak in order to reduce the potential risks.