Gamma irradiation is important agent used to improve the productivity and quality of many plants. The present study was carried out to evaluate the effectiveness of different doses of gamma rays (0, 5, 10, 15, 20, 25, 30 kR) on germination percentage, vegetative growth, photosynthetic pigments, oil yield, oil components and total phenolic content of Ocimum basilicum L during the two successive seasons of 2017 and 2018 at the Experimental Farm of Sakha Horticulture Research Station, Kafr El-Sheikh Governorate, Egypt. Results showed that low doses of gamma irradiation significantly increased germination percentage, plant height, number of branches, fresh and dry weight per plant and per fed, chlorophyll a and chlorophyll b, essential oil percentage, oil yield per plant and per fed and essential oil main components. Increasing gamma rays doses significantly reduced germination percentage, vegetative growth characters and oil yield while total carotenoids content and total phenolic content significantly increased as a defensive effect to the increase in irradiation doses. The study suggested 10kR dose as seeds treatment for increasing basil plants production through enhancing germination percentage, vegetative growth, fresh yield, essential oil yield and essential oil components.