Essential oil from a variety of sources has been proven to be effective antimicrobial for the past decades. However, its efficacy when applied to the food system is a major consideration. This study aimed to evaluate the antimycotic property of lemon grass (Cymbopogon citratus Stapf.) essential oil (LGEO) and its effect on the microbial stability and quality of ready-to-drink (RTD) moringa (Moringa oleifera Lam.) beverage. Agar well diffusion assay was used to screen the antimycotic activity of the essential oil against common fungi that may grow in ready-to-drink beverages. The largest zone of inhibition (10.67 ± 1.15mm) was observed against the yeast Debaryomyces hansenii. It was followed by Hansenula anomala and Torulopsis candida with zones of inhibition of 5.67 ± 0.58 mm and 3.67 ± 0.58 mm, respectively. For molds, Penicillium roqueforti and Mucor rouxii were reported to have 2.33 ± 0.58 mm and 2.00 ± 1.00 mm zones of inhibition, respectively. Agar dilution method was performed to determine the minimum inhibitory concentration (MIC) against each microorganism. D. hansenii was the most susceptible yeast which was inhibited by 1.5 uL/mL of LGEO. It was followed by H. anomala and T. candida which were inhibited at minimum concentrations of 3 uL/mL and 5 uL/mL, respectively. Microbial count monitoring of moringa beverage containing different concentrations of LGEO was performed within 10 days and 10 uL/mL of LGEO was found to be the most effective concentration in maintaining the stability of the beverage. The addition of LGEO combined with heat treatment exhibited a synergistic effect in the preservation of RTD moringa beverage. Sensory evaluation results indicated that addition of LGEO did not negatively affect the organoleptic properties of the drink. Results showed that LGEO is an effective antimycotic agent and a potential natural preservative in RTD moringa beverage.