Background: Dermatophytosis (ringworm) is a zoonotic fungal skin infection caused predominantly by Microsporum canis, Microsporum gypseum and  Trichophyton spp. It is highly transmissible and, while normally self-limiting, could be problematic due to its potential to cause disease in certain human  populations. The occurrence and associated risk factors of dermatophytoses in dogs presented at three veterinary clinics in Osogbo, and Ilorin, Nigeria between July and November 2019 were investigated in this study. Methodology: This was a descriptive cross-sectional study of 325 dogs with lesions suggestive of dermatophytosis, selected by simple random sampling from three veterinary clinics in Osogbo and Ilorin, purposively selected for the study due to high patronage of the veterinary hospitals by dog owners.  Using conventional mycological sampling techniques, plucked hairs and skin scrapings were obtained the dogs. The samples were emulsified in 10%  potassium hydroxide, examined microscopically for fungal elements and cultured using standard mycological procedures. Information on dog  demographic characteristics and risk factors for dermatophytosis were collected using structured questionnaire. The association between risk factors  and demographic variables with the occurrence of dermatophytoses was determined using Chi-square test (with Odds ratio and 95% confidence interval)  and p value < 0.05 was considered statistically significant. Results: Positive cultures for dermatophytes were obtained from samples of 48 (14.8%) dogs  with M. canis 37.5% (18/48), M. gypseum 27.0% (13/48) and T. mentagrophytes 8.3% (4/48). Other fungi identified were Aspergillus flavus 12.5% (6/48) and  Malassezia canis 12.5% (6/48). The age distribution of positive dogs were < 1 year (50.0%, n=24), 1-3 years (29.2%, n=14) and > 3 years (20.8%, n=10),  while the risk factors associated with dermatophytosis included sex of dogs (p=0.0428), history of dermatophytosis (p<0.0001), clinical presentation  (p<0.0001) and lesion type, especially kerion and pustular lesions (p=0.0297). Conclusion: These findings established the occurrence of dermatophytosis  in dogs kept for companionship (i. e., pets), security and breeding purposes in the two States in Nigeria. Our findings underscore the need for routine  mycological investigations in dogs to facilitate early detection of cases and prompt institution of treatment interventions, thereby preventing zoonotic  transmission of dermatophytes to their owners, handlers and veterinarians.