<p><i>Phaeoacremonium iranianum</i> is a phytopathogenic fungus of the phylum <i>Ascomycota</i> that attacks various woody plants, including grapevines and olives. This fungus can cause serious diseases on grapevines, such as Esca disease and Petri disease, characterized by symptoms such as wilting and necrosis. Infection occurs primarily through wounds in moist conditions. This study aimed to evaluate the antifungal potential of eight commercially derived essential oils (EOs), including cinnamon (<i>Cinnamomum verum</i>), cypress (<i>Cupressus sempervirens</i>), lavender (<i>Lavandula angustifolia</i>), rosemary (<i>Rosmarinus officinalis</i>), star anise (<i>Illicium verum</i>), sweet orange (<i>Citrus sinensis</i>), and thyme (<i>Thymus vulgaris</i>) in two chemotypes, thymol, and linalool, against <i>P. iranianum</i> under in vitro conditions. The antifungal effect of essential oils (EOs) was evaluated at concentrations ranging from 0.006 to 0.24%, with assessments conducted on days seven and 14 after inoculation. The results showed that the EOs of cinnamon and thyme (thymol) exhibited the strongest antifungal activity, completely inhibiting mycelial growth even at the lowest concentration. In comparison, higher concentrations were required for the other EOs to achieve similar results. For example, the EOs of sweet orange and cypress demonstrated weaker and less consistent antifungal effects. This study highlights the potential of essential oils (EOs) as natural alternatives to synthetic fungicides. Furthermore, the results suggest that the mechanisms underlying the antifungal potential of EOs require further investigation to enable their practical application.</p>