Roselle petals contain high anthocyanins, a good antioxidant, and natural dark red colorants. Anthocyanins help in reducing risks of cardiovascular disease and colon cancer. But anthocyanins are easily affected by extraction process. Therefore, this study proposed a new method of extracting anthocyanins using ultrasonic-assisted extraction (UAE) from roselle petals with three extraction parameters. The extraction parameters are sample�s particle size (0.125, 0.375 and 0.625 mm), solvent to solid ratio (10:1, 15:1 and 20:1 mL solvent/g solid) and extraction time (5, 10 and 15 min). The optimization of process parameters aims to achieve the highest extraction yield of extract, Total Anthocyanins Content (TAC), and Antioxidant Activity (AA). The results show that 0.125 mm of particle size, 10:1 mL solvent/g solid, 15 min of extraction obtained the best percent mass yield (64.72), TAC (70.97 mg/L), and AA (90.05). Method-wise, this study showed that the ultrasonic-assisted extraction gives better quality of roselle petals extracts than the maceration extraction. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.