Abstract: This study was undertaken to investigate the prevalence and pathology of naturally occurring oral lesions in sheep in Mosul area, Iraq. Whether a relationship exists between factors such as age, breed and type of management and the prevalence of the oral lesions was also studied. Oral lesions were found in 104 out of 1130 (88.8%) examined sheep and dental abnormalities were the most common of these lesions and constituted 77.2% of the total number of oral lesions. The various types of oral lesions arranged in order of decreasing frequency were tooth discoloration 81.68%, gingivitis 27.52%, loss of teeth 11.06%, Malarrangement of teeth 10.62%, incisor wear 10.53%, healed ulcers of the gum 6.46%, broken mouth 5.84%, dental caries 2.30%, acute ulcers of the gum 1.41%, abscesses 0.18%, granulomatous reactions 0.18%, papilloma 0.09%, basal cell carcinoma 0.09%, dermatophytosis 0.09% and contagious pustular dermatitis 0.09%. Infection with the microscopic form of Sarcocystis sp. was encountered in the tongue of 104 sheep that were examined histopathologically, with a 100% prevalence. Gross and microscopic features of the various types of lesions were similar to those described in the literature. Statistically significant differences were found between the prevalence of the oral lesions in various age groups of sheep. Thus, the prevalence was significantly higher (p<0.05) in sheep of the age group >1.5 to <2 years and the least in the age group of >5 years. The oral lesions were more common in Awassi breed 82.67% than in the Karadi 12.95% and Hamdani 4.38% breeds and these differences were statistically significant (p<0.05). Additionally, the oral lesions were more prevalent among sheep reared indoor 89.04% than in sheep reared outdoor 10.96% and this difference was statistically significant (p<0.05).