Reactive dyes can be found in large quantities in textile industry wastewater due to their widespread use for dyeing cotton fabrics and their durable nature. In the treatment of wastewater containing dyestuffs in this class, advanced treatment methods have become necessary due to the inadequacy of conventional treatment methods and their disadvantages. For this reason, electro-Fenton, an electrochemical advanced oxidation method, is a strong alternative as a treatment technology that provides complete disintegration of dye molecules. In this study, the electro-Fenton method was used to treat model wastewater containing the reactive azo dye Sumifix Yellow EXF. The electro-Fenton process is based on the in situ generation of hydroxyl radicals (⦁OH), a strong oxidant, using Fe2+ and H2O2 released at the electrodes or added from outside. In the electrochemical cell used, carbon fiber was used as the cathode and iron was used as the anode. While Fe2+ ion was produced at the anode, H2O2 was added to the cell externally. In the experiments carried out at room temperature, a 250 mL glass beaker was used as a reactor. In the study, the optimization of the parameters was achieved by using the classical experimental design method. According to this method, one parameter is changed and other parameters are kept constant. In order to achieve the highest dyestuff removal, experiments were conducted by varying the voltage (5–10 V), H2O2 concentration (9–74 mM), Na2SO4 concentration (6–25 mM), and pH (3-5), and the impact of these factors on dye removal and energy consumption was evaluated. It was found that for the best dye removal, voltage is 7.5 V, the H2O2 concentration is 74 mM, the Na2SO4 concentration is 25 mM and the optimum pH value is 4. At these values, 98.14% removal at 30 minutes was achieved with an energy consumption of 7.98 Wh/L. The electro-Fenton method was found to be a highly effective approach for wastewater treatment and environmental remediation, showing remarkable dye removal efficiency with reasonable energy consumption under optimized conditions.