The present work aimed to estimate the optimum period for weed control and predict yield losses coming from weed competition of three Sesame varieties under various weed removal periods. A field experiment was conducted during the season of 2023 by making the study field free of weeds by hand weeding starting from sesame plant emergence until periods of 1, 2, 3, 4, and 5 weeks. Then, weed plants are allowed to grow after these periods till the end of the growing season. Results of the study determined that the optimum period for wee control from the sesame plants’ emergence until the third week after emergence according to acceptable yield losses which was estimated by 10-12% in comparison to the yield of sesame plants served by weedy-free throughout the growing season. yield losses of sesame resulting from weed competition all over the growing season ranged from 66.42 to 95.95% for the three cultivated sesame varieties. The results of the present work recommend making the field free of weeds from emergence until the third week of the sesame plant age and not delaying the control operation by using any weed control that is still effective against weeds until this period to avoid unacceptable loss of the economic yield.