The objective of this study was to optimise the extraction conditions for phenolic compounds from limau purut (Citrus hystrix) peels using response surface methodology (RSM). A central composite rotatable design (CCRD) was applied to determine the effects of ethanol concentration (%), extraction temperature (oC), and extraction time (min) on total phenolic content (TPC) from limau purut (Citrus hystrix) peels. The independent variables were coded at five levels and their actual values were selected based on the results of single factor experiments. Results showed that ethanol concentration was the most significant (p