Given the global issue of water scarcity, the recovery and treatment of wastewater, as landfill leachate (LL), are of utmost importance. The presence of colloids in LL scatters UV irradiation, limiting the effectiveness of the photo-Fenton process. However, using ultrasound (US) technology can degrade the organic matter in LL and produce H2O2 and sonoluminescence, which are crucial in the photo-Fenton process. With its focus on practical applications, this research aims to improve the quality of LL treatment, thereby addressing a significant and urgent environmental challenge. Also, this research aimed to identify the optimal operational parameters that improve the self-generated H2O2 and sonoluminescence due to the US and to evaluate the improvement of the quality of LL using the sono-photo-Fenton.<br /> Actinometry was used to measure the sonoluminescence produced in this study. The highest amount of H2O2 and sonoluminescence was formed at 864 kHz and a US power of 500 W, obtaining 2.63 mg/L of H2O2 and 6.89 x 10-5 J/s of sonoluminescence. The optimised conditions were used in the sono-photo-Fenton process runs towards the degradation of a simulated LL (SLL) to evaluate the effect of concentration of Fe+2 and concentration of H2O2 on the depuration of SLL, obtaining a synergy index of 1.25.