The present study was aimed to determine the inhibitory effects of Curcuma longa L. essential oil (CLEO) against the growth and zearalenone (ZEA) production of Fusarium graminearum. Chemical profiling of CLEO was carried out by GC-FID analysis and major compound was ar-turmerone (53.10%). Antifungal activity of CLEO was assessed by using micro-well dilution method, and minimum inhibitory (MIC) and minimum fungicidal concentrations (MFC) were determined as 2450 and 3300 μg/mL, respectively. Interestingly, ROS played a major role in antifungal activity as evidenced by reactive oxygen species estimation from CLEO treated fungal cultures. Further, Scanning electron microscopy observations were carried at MIC and MFC concentrations. Results indicated that, CLEO significantly affected the morphology of mycelia and spore structures compared to untreated control culture. Effects of CLEO on fungal biomass as well as ZEA production were assessed by dry-weight and UHPLC analysis, respectively. Results indicated that, fungal biomass and zearalenone production was completely inhibited at 3500 and 3000 μg/mL, respectively. The results of the study conclude that, CLEO may find a potential application in the food industry to control the fungal infestation and ZEA contamination. •GC–MS analysis of Curcuma longa essential oil (CLEO) revealed presence of 35 compounds.•ABTS and DPPH antioxidant activities of CLEO were 48.35 and 33.81 μg/mL.•MIC and MFC values of CLEO on Fusarium graminearum were determined as 2450 and 3300 μg/mL.•CLEO inhibited fungal biomass and zearalenone production at 3500 and 3000 μg/mL.•CLEO showed antifungal activity through ROS induced apoptotic cell death.