This study aimed to investigate the effects of the supplementation of defatted mealworm larvae meal fermented with probiotics to the diet of broilers reared under normal stocking density (NSD) and high stocking density (HSD) on the morphometric characteristics and mineral contents of tibia bone of broilers. A total of 450 one-d-old Ross 308 male broiler chicks were randomly distributed into six groups of similar mean weight, each containing five replicates. The experimental treatments were arranged as a 2 × 3 factorial design, incorporating two levels of stocking density (12 birds/m², designated as NSD, and 18 birds/m², designated as HSD) and three different diets in mash form: CONT- a corn-soybean meal-based diet containing no fermented defatted mealworm larvae meal (FDM) (0%); FDMLP- the diet obtained by supplementing defatted mealworm larvae meal (DM) fermented with Lactobacillus plantarum to the CONT diet (0.4%); FDMLB- the diet obtained by supplementing DM fermented with Lactobacillus brevis to the CONT diet (0.4%). HSD significantly aggravated the morphometric parameters (weight, length, weight/length index, diameter of diaphysis and medullary canal, tibiotarsal index and breaking strenght) and decreased mineralization (ash, Ca and P contents) of the tibia of broilers, whereas the FDMLP and FDMLB diets improved tibia mineralization and morphology except its medullary canal diameter and ribusticity index of broilers due to the results of enhanced mineral absorption. In conclusion, the use of FDMLP and FDMLB as new antibacterial feed additives in broiler diets regardless of stocking density was able to improve tibia mineralization and morphology except its medullary canal diameter and ribusticity index of broilers due to the results of enhanced mineral absorption.