A B S T R A C TOlive anthracnose is an important fruit disease in olive crop worldwide. Because of the importance of microbial phyllosphere to plant health, this work evaluated the effect of cultivar on endophytic and epiphytic fungal communities by studying their diversity in olives of two cultivars with different susceptibilities to anthracnose. The biocontrol potency of native isolates against Colletotrichum acutatum, the main causal agent of this disease, was further evaluated using the dual-culture method. Fungal community of both cultivars encompassed a complex species consortium including phytopathogens and antagonists. Host genotype was important in shaping endophytic but not epiphytic fungal communities, although some host-specific fungal genera were found within epiphytic community. Epiphytic and endophytic fungal communities also differed in size and in composition in olives of both cultivars, probably due to differences in physical and chemical nature of the two habitats. Fungal tested were able to inhibited C. acutatum growth (inhibition coefficients up to 30.9), sporulation (from 46 to 86%) and germination (from 21 to 74%), and to caused abnormalities in pathogenic hyphae. This finding could open opportunities to select specific beneficial microbiome by selecting particular cultivar and highlighted the potential use of these fungi in the biocontrol of olive anthracnose.