Abstract. The study investigated the effects of supplementing broiler diets with poppy (Papaver somniferum L.) seed meal (PSM) on growth performance, nutrient digestibility, faecal microbiota, and blood profiles. A total of 250 unsexed 1 d old broilers were allocated to five distinct treatment groups. PSM was incorporated into the diets at varying levels: 0 % (PSM0), 5 % (PSM5), 10 % (PSM10), 15 % (PSM15), and 20 % (PSM20). The findings indicated that growth performance, including weight gain, feed intake, and feed conversion ratio (FCR), was significantly improved (P<0.05) in the PSM20 group compared to the control. However, carcass weight experienced a notable decrease (P<0.05) in the PSM20 group. Regarding nutrient digestibility, PSM supplementation led to reduced crude protein digestibility. Nevertheless, apparent metabolizable energy and ash content were significantly enhanced (P<0.05) in the PSM15 and PSM20 groups. Notably, faecal microbiota also experienced substantial improvement (P<0.05) in the PSM20 group. In conclusion, the study demonstrates that incorporating poppy seed meal at a rate of 20 % in broiler diets enhances growth performance, improves nutrient digestibility, and positively influences faecal microbiota composition.