Agriculture faces many difficulties related to phytopathogenic fungi leading to quantitative and qualitative losses of crops. The use of essential oils against these fungi is one of the alternatives. This study focused on the antifungal activity and phytotoxicity of Vitex simplicifolia Oliv. leaves essential oil. Firstly, we extracted the essential oil from the leaves by hydrodistillation. Subsequently, seven fungal isolates were evaluated for their sensitivity to the essential oil on Potato Dextrose Agar (PDA) media at 0.1; 0.25 and 0.50%. Evaluation of the phytotoxicity of the essential oil was performed on sorghum seeds on a sterilized sand substrate. At the seventh day after incubation, the most sensitive fungi to the essential oil are Fusarium moniliforme, Colletotrichum graminicola and Curvularia lunata. The most sensitive fungus to the essential oil at 0.50% is Colletotrichum graminicola with 77.21% inhibition rate at the seventh day after incubation. Phytotoxicity evaluation showed that for all biomass parameters measured there is no significant difference between treatment with the essential oil and treatment with the fungicide control. At the end of this study, it appears that Vitex simplicifolia essential oil has a high antifungal activity. This essential oil has not shown toxicity on sorghum growth parameters. Therefore, this oil can be used in organic farming.