The main aim of this study is to determine the chemical compounds ofOriganum compactumessential oils (OCEO) at three phenological stages (vegetative, flowering, and post-flowering) and to evaluate their antifungal activity against three dermatophytes fungal strains:Trichophyton violaceum, Trichophyton tonsurans, andTrichophyton mentagrophytesusing direct contact method. The main compounds of OCEO are carvacrol, thymol, p-cymene, and γ-terpinene. Oregano EOs showed important antifungal activities with some variability between EOs and fungal testing. At a concentration of 0.75% (v/v), the best inhibition values showed with OCEO at vegetative stage againstTrichophyton mentagrophytes(95.17%),Trichophyton tonsurans(92.47%), andTrichophyton violaceum(91.41%). The OCEO at vegetative stage also showed the best IC50 (concentration of an inhibitor where the response is reduced by half) values of 52.86, 0.56, and 0.57% (v/v) againstTrichophyton mentagrophytes,Trichophyton tonsurans, andTrichophyton violaceum, respectively. The findings reveal that OCEO is a good source of anti-dermatophytes agents.