Onychomycosis is one of the most common diseases in the field of dermatology. It refers to the fungal infection of the nail plate or nail bed with high incidence in the general population. The available treatment options for onychomycosis have limited use due to side effects, drug interactions, and contraindications, which necessitates the application of an alternative treatment for onychomycosis. In the recent years, lasers and photodynamic therapy (PDT) have been recognized as alternative treatment options. Most of the previous studies have found them to be safe and effective treatment modalities in this indication; however, the results varied greatly and the in vitro and in vivo outcomes are contradictory. In the present review, studies related to the mechanism of action of lasers and PDT for the treatment of onychomycosis will be discussed, with a focus on to find explanation to the contradictory results.