Red onions are valuable sources of bioactive metabolites with antimicrobial effects, showing promise as clinical treatments for antibiotic-resistant bacterial infections. This study aimed to compare the antimicrobial and antioxidant effects of different extractions of red onion peel extract. For this purpose, extraction was first carried out using ultrasonic methods in methanol and immersion methods in ethanol and acetone. Antimicrobial properties were evaluated using agar diffusion and determination of the minimum inhibitory concentration for Pseudomonas aeruginosa, Escherichia coli, Bacillus cereus and Staphylococcus epidermidis. Antioxidant tests, total phenol content, and anthocyanin were also assessed.The results showed that the phenolic content of ethanol, acetone, and methanol extracts was 1.256, 1.232, and 1.187 mg/g of gallic acid, respectively. The antioxidant activity of the respective extracts was 74.83%, 63.88%, and 78.38%. The anthocyanin content of the extracts was 4.475301, 4.525398, and 3.022498 mg/L, respectively. In the antimicrobial tests, no inhibition zones were observed for the Gram-negative bacteria Pseudomonas aeruginosa and Escherichia coli, but inhibition zones were present for Bacillus cereus and Staphylococcus epidermidis. The minimum inhibitory concentration of the acetone extract for Bacillus cereus was higher than for other bacteria (3125 µg/ml), while methanol and ethanol extracts ranked second and third with concentrations of 390 µg/ml and 48.8 µg/ml, respectively. Overall, the minimum inhibitory concentration of the extracts against Gram-negative bacteria was higher than that for Gram-positive bacteria. Inconclusion, red onion peel extract demonstrated significant antimicrobial activity, especially against Gram-positive bacteria, highlighting its potential as a natural therapeutic agent.