Ingredient particle size (PS) is known to affect pellet quality (PQ). The literature supports improved performance when PQ is improved. Recent research indicated that ingredient PS also affects amino acid (AA) digestibility. The objectives of this study were to determine the effects of soybean meal (SBM) PS on feed milling efficiency, PQ parameters, broiler performance, and processing characteristics. Dietary treatments were created by reducing SBM PS with three hammermill screens (3/32” (2.4 mm), 7/32” (5.6 mm), and 10/32” (7.9 mm)). These screens represent the treatments used in each experiment. Experiment 1 was conducted at the pilot feed mill at West Virginia University using the finisher period feed that was provided in experiment 2. Experiment 1 was arranged in a 3 x 3 Latin Square design with three 453.6 kg replicate batches per treatment. Hot pellet temperature and production rate were collected in duplicate and provided as an average. PQ analyses were conducted 24-h post-pelleting. In experiment 2, 1,152-day-old male HR708 broilers were housed in 12 replicate floor pens per treatment. Treatments were arranged in a randomized complete block design with a pen of 32 birds serving as the experimental unit. Birds were fed one of three treatment diets varying in SBM PS (3/32”, 7/32”, or 10/32”) from d1-42 in a three phase (starter, grower, finisher) feeding program. Birds and feed were weighed to calculate FI, LWG, and mortality corrected FCR at the end of each feeding phase. On d42, two broilers per pen were individually weighed, stunned, exsanguinated, and slaughtered to determine processing yields and gizzard weights. All data were analyzed using the GLM procedure of SAS using a one-way ANOVA. The F-protected Fisher!s LSD test was used to separate means when P≤0.05. In experiment 1, SBM PS did not affect hot pellet temperature or production rate (P>0.05). However, PQ improvements were apparent when the small SBM (3/32” screen) was used (P<0.05). It is noteworthy that small SBM did cause the pellet die to plug during each manufacturing replicate. In experiment 2, d1-42 broiler performance demonstrated higher FI, LWG, and FCR when the small SBM (3/32″ screen) was provided compared to when larger SBM (7/32″ and 10/32″ screens ) was provided. These data support previously reported findings of reduced AA digestibility when small SBM is provided to broilers. FI likely increased to meet AA needs, providing additional nutrients for maximal growth. However, FCR was negatively impacted. Finally, SBM PS did not affect processing yields (P>0.05).