This study investigated the eff ects of dietary probiotics (Lactobacillus reuteri E81 [LRE], Lactobacillus rhamnosus GG [LRG]), yeast (Saccharomycescerevisiae S81 [SCS]), and their combined supplementation on fattening performance (BW, DWG, FI, and FCR), meat quality, and rumen and duodenumhistology in lambs. The study material comprised ninety 2.5-month-old Anatolian Merino lambs, and the trial was conducted for 70 days. Nine trialgroups, each composed of 10 animals, were established. This study demonstrated that, when compared to the control group, the best fatteningperformance was achieved in the lambs that received 600 ppm of dietary LRE. Neither visceral organ weights nor rumen and duodenum histologywas aff ected in the groups that received the tested feed supplements. Of the meat colour parameters investigated, the L* value was observed to haveincreased in the groups that were given feed supplements, excluding Groups LRE-600 and SCS-300. It was determined that the probiotic supplementshad no eff ect on the a* and b* colour parameters, but aff ected the meat pH value. In conclusion, the assessment of the eff ects of diff erent doses ofdietary probiotics, yeast, and probiotic-yeast combinations on performance parameters, visceral organ weights, and meat quality in Anatolian Merinolambs showed that the best results were achieved in the group that received 600 ppm of LRE alone.