Thyme (Thymus vulgaris L.) is seasoning and medicinal herb used in pharmaceutical purposes due to high phenol content. Egyptians used it for embalming and making perfumes. Greeks used thyme for peppering some sorts of cheeses and they were adding it to some drinks and smoke-dried meat. In its content are borneol, carvacrol, thymol, saponins, tannins, glycosides, vitamins A, C, D, B-complex, magnesium, phosphorus, potassium and zinc. Analysis showed high content of vitamin C and phenols, there by a high antioxidant capacity. In this research, two year old plants were placed under three different monochromatic lights of red and blue spectrum and were determined for their functional components. The analyses were carried before illumination, after two weeks, and after four weeks of illumination with LED lights. Statistically significant differences were observed depending on duration of illumination. Statistically significant difference weren’t observed among the variants of treatments; however, it was observed that the plants under red light developed a larger number of lateral shoots. Plants under blue light had the highest vitamin C and proline content, while under a combination of red+blue light had the highest phenolic concentration and antioxidant capacity. A large body of evidence are confirming that additional lighting with monochromatic lights have morphological and physiological effects on plants. Controlling the light spectral composition is useful to achieve higher productivity or greater nutritional quality of the commercial crops, although the efficiency of the spectral composition differs depending on the plant species and phase with the additional illumination.