A field experiment was conducted under the agro-climatic conditions of Doon valley, Uttarakhand during 2008 to assess the performance of four harvesting times (H1-115 days, H2- 135 days, H3-155 days and H4-175 days after planting) of Thymus serpyllum L. The number of branches/ plant found maximum in H1 harvesting. The parameters i.e. fresh and dry herbage (leaves and small twigs) yield showed greater response in 115 days after planting, whereas fresh oil yield maximum in H3 harvesting. The quality of Thyme essential oil was evaluated at different harvesting times using GC/MS. Thymol content was rich in all the four harvestings (34.61- 49.53%), though it was maximum in H2 (49.55%) followed by H1 (42.87%), H3 (42.51%) and H4 (34.61%) harvesting times.