The industrial use of natural dyes for textile coloration has significantly increased in recent years, due to their environmentally friendly nature. However, the dyeing process with natural dyes requires the use of auxiliary chemicals to achieve the desired product quality. This work aimed to evaluate the feasibility of the electrochemical oxidation process, using a boron-doped diamond anode, to treat the wastewater streams from the different stages of the eco-dyeing of wool-blend fabrics (pretreatment, dyeing, soaping, and fixation), using a lac dye and several auxiliary chemicals. The experimental results showed that, for most of the wastewater streams evaluated, the electrochemical treatment was effective in removing the organic load, with a high degree of mineralization of the organic compounds. The wastewater from the dyeing stage presented the highest organic load, with a chemical oxygen demand (COD) of 2130 mg L−1. After 8 h of electrochemical treatment, a COD removal above 97% was observed for this wastewater. The presence of chloride in the fixation wastewater, even at low concentrations, enhanced the current efficiency of the treatment. Contrarywise, chitosan, present in the pretreatment wastewater, hindered the oxidation of the organic compounds through hydroxyl radicals.