Bactrocera oleae is the most important economic pest of olive worldwide. In the present study, population fluctuations of the olive fruit fly were investigated using yellow sticky traps baited with sex pheromone and MacPhail traps containing food bait during 2023–2025 in the Jabalbarez region. The parasitism of Cyrtoptyx latipes on the larvae was investigated. The results showed that Bactrocera oleae has three generations in the Jabalbarez, occurring in early August, early September, and October, respectively. The olive fruit fly overwinters mainly as an adult within olive orchards, although in some cases it overwinters as a larva inside fruits remaining on the trees. The first and last captures of adult insects were recorded in early March and early January. Trap catches increased as the weather warmed from April (inflorescence formation stage) toward summer. Peak captures of adult insects, based on host plant phenology, were recorded during the fruit color change stage (July and August) and the fruit ripening stage (September). Adults laid eggs in the fruits in late July, coinciding with the pit-hardening stage of olive fruits. The capture rate was positively related to fruit infestation and olive tree phenology (r = 0.72, r = 0.90). The activity of Bactrocera oleae was positively correlated with ambient temperature. The C. latipes emerged in the orchard in late August, coinciding with the fruit color change stage and the oviposition activity of olive fruit fly. The highest larval parasitism rates were recorded in early October, reaching 59.09% and 66.6% in 2024 and 2025.