Plant essential oils are being taken into greater consideration because their constituents have unique antioxidant and antimicrobial properties which makes it a good alternative to synthetic antioxidant and chemical pesticides. The present study was conducted to evaluate the antioxidant and antifungal activities of lemongrass (Cymbogon schoenanthus L.), sage (Salvia officinalis L.) and thyme (Thymus vulgaris L.) essential oils. The chemical compositions of three hydrodistilled essential oils were analyzed by Gas Chromatography-Mass Spectrometry (GC/MS) system. The major components in lemongrass, sage and thyme essential oils were D-limonene (52.34%), eucalyptol (43.17%) and thymol (27.94%), respectively. The antioxidant activities of three essential oils were evaluated by using reducing power assay and DPPH methods. The highest antioxidant activity was recorded for lemongrass, followed by sage and thyme essential oils, respectively. The effect of thyme, sage and lemongrass essential oils at two concentrations on the control of pea root-rot and damping-off diseases were determined in vitro and in vivo. The results showed that application of oils significantly reduced the mycelial growth, disease severity and increase plant growth parameters. Thyme essential oil (10% conc.) gave the best results followed by lemongrass oil (10% conc.) while sage oil (5% conc.) gave the least effect. These data denoted that the three essential oils possess antimicrobial and antioxidant properties, so these essential oils can be used as natural antioxidant in food and pharmaceuticals and also in biological control.