Allelopathy plays crucial role in effective weed control. Opium (Papaver somniferum L.) crop release different allelochemicals at maturity which have potential to act as natural weed killer in different crops. Phytotoxic effect of poppy (P. somniferum) was examined on emergence and initial seedling growth of red rice (Oryza punctate L.). Aqueous extract of different plant parts (leaves, stem and flower) was used at various concentrations (0.25%, 0.5%, 1%, 2%, 4% and 8%) along with distilled water as control. The aqueous extracts of leaves, stem and flower of P. somniferum significantly inhibited the emergence, seedling growth as well as root length (cm), shoot length (cm), fresh weight (g) and dry weight (g) of O. punctata. Maximum mean emergence time (9.18 days) and minimum shoot length (1.13 cm) emergence index (0.89) and emergence percentage (6.67%) was observed under fruit extract at 8% concentration. P. somniferum aqueous extract of stem at 8% concentration took maximum time to complete 50% emergence and gave minimum root length, fresh weight, and dry weight of O. punctata. Based on these finding it can be concluded that the phyto-chemicals present in P. somniferum can be used as eco-friendly O. punctata growth inhibitor to manage this weed in crops especially under organic cropping.