The present study was conducted during the two seasons of 2020 and 2021 to determine the effects of pre-harvest treatment with thyme oil on grape (Vitis vinifera) Flame seedless cv. fruit quality during cold storage conditions (0±1°C and 90±5% RH). Clusters were sprayed with thyme oil at 0.2% 48 hours before harvest, while the control was sprayed by water. Fruit quality was measured at harvest time and then every 15 days of cold storage. This experiment was arranged in a factorial design with three replicates. The results in this study confirmed that grape clusters treated with thyme oil at 0.2% recorded the highest marketable percentages and visual appearance of clusters. In addition, this treatment recorded the highest berry contents of ascorbic acid and total soluble solids (TSS/TA) comparable to the control. Thus, it could be recommended to use thyme at 0.2% as a safe pre-harvest treatment maintain the quality of Flame Seedless grapes during cold storage.