<p>Fungal nail infections (onychomycosis) remain challenging to treat due to prolonged therapy, poor cure rates, and safety concerns associated with oral antifungal agents. Although topical formulations are the preferred treatment option, their clinical effectiveness is constrained by the dense keratinized nail barrier. While formulation-driven strategies and device-based therapies have expanded the therapeutic approaches for onychomycosis, their clinical efficacy remains suboptimal, pointing towards the need for pre-clinical evaluation of their performance using more clinically relevant models during the development stage. Nail-integrated model systems provide a platform for evaluating the efficacy of novel antifungal topical treatments in a controlled disease-mimicking environment, thereby enhancing the likelihood of clinical success. This review critically evaluates in vitro and ex vivo models, including keratin-supplemented media, keratin biomembranes, animal hooves, and human nails, focusing on their physiological relevance, advantages and inherent limitations. Ex vivo experimental model designs reported in recent studies are discussed to spotlight their application in evaluating topical formulations and device-based interventions. Ex vivo human nail models, when rationally designed to reflect the structural and pathological architecture of onychomycosis, offer robust, clinically predictive platforms for formulation and device optimization, dose and treatment frequency and comparative efficacy assessment. Infected animal hooves serve as a surrogate for human nails and provide reproducible experimental models for screening the antifungal efficacy under standardized conditions. The available ex vivo data support the utility of these models in predicting clinical performance of antifungal formulations and devices during pre-clinical development; however, broader industrial adoption will require standardized and harmonized protocols, as well as further clinical validation.</p>