This investigation aimed to assess essential oils chemical composition, antioxidant, and antimicrobial activity from Melaleuca alternifolia and Citrus hystrix peel. The essential compositions were identified using gas chromatography-mass spectrometry (GC-MS). Antioxidant activity was evaluated using the DPPH assay. Antimicrobial activity and synergistic effects of combined essential oils were assayed against five selected microbial strains (Candida albicans, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Staphylococcus pyogenes, and Acinetobacter baumannii. In this research, GC-MS analysis revealed the presence of 25 compounds in Citrus hystrix peel essential oil, of which citronella was a major component, whereas terpinen-4-ol was a key constituent among 25 compounds detected in Melaleuca alternifolia essential oil. Melaleuca alternifolia essential oil exhibited higher antioxidant activity with IC50 of 79.044 ± 8.183 ug/mL than Citrus hystrix peel essential oil with IC50 of 572.075 ± 71.005 ug/mL. Minimum inhibitory concentration values of Citrus hystrix peel essential oil were found between 0.250% and 1.000%, whereas minimum inhibitory concentration values of Melaleuca alternifolia essential oil were recorded between 0.0078% and 0.125%. The combination of essential oils from Melaleuca alternifolia and Citrus hystrix peel displayed the powerful synergistic antimicrobial effectiveness against three of the five studied microbial species. The additive antimicrobial effects, however, were documented in blended essential oils against Staphylococcus aureus and Candida albicans.