In this study, effect of different harvesting time on loss ratio of olive caused by Olive fruit fly [Bactrocera oleae (Gmelin) (Diptera: Tephritidae)], olive oil yield and quality on the varieties; Ayvalik (growing Akhisar district of Manisa), Memecik (growing Torbali district of Izmir) and Erkence (growing Urla district of Izmir), in 2008-2009 were studied. In this study, the highest Olive fruit fly population was recorded generally in October and November. Besides, the infested fruit ratio was recorded up to 100 % as a result of suitable growing conditions in 2009. In different harvesting time; it was determinate that there was not any considerable change in fruit weight, fruit oil ratio accessed the highest value while fruit maturity value was between 2.5-4.0 in third and fourth harvesting time (November) and fruit drops increased as fruit maturating increase. Depends on results of this study, early harvesting time was found enough as alone control method against Olive fruit fly damage in Ayvalik variety (Akhisar) both two years but in Memecik variety (Torbali) while abundant harvest year and Olive fruit fly population was low. Early harvesting time was not enough as alone control method of Olive fruit fly for Erkence variety (Urla) both two years and Memecik variety (Torbali) while conditions are suitable for pest and poor harvest year. However, considering olive oil yield and quality, it was determined that at the beginning of November when fruit maturity value was between 2.5-3.5, application of early harvesting decreased Olive fruit fly infestation under all circumstance in all varieties.