Thrips tabaci Lindeman (onion thrips) have become a serious pest threatening onion cultivation. The present study investigated the impact of three planting dates on T. tabaci incidence on onion (Giza 20 variety) for two years (2021-22 and 2022-23). The findings revealed that the T. tabaci recorded 4 peaks in the 1st planting date, the 2nd with an average population density (677.21 and 703.24 individual/plant), followed by the 2nd with 500.05 and 602.13 insects. While the 3th planting date recorded three peaks (385.77 and 494.04 individual/plant). The interaction between plant age, natural enemies, climatic conditions and T. tabaci population density resulted in a strong relationship affecting onion yield.