In this paper, a space Vector modulation scheme (SVMS) to enhance the performance of the single-stage three-phase grid-tied SEPIC-based differential inverter is presented. Compared to the traditional modulation schemes, the proposed modulation scheme offers a significant reduction in the peaks of output voltages and input currents of the utilized SEPIC modules at the same voltage gain. Moreover, the peak voltages of the utilized capacitors in SEPIC converters are reduced. Therefore, the voltage stresses, conduction losses, and switching losses have been decreased, and the system efficiency has been increased in accordance. The proposed SVMS is implemented by employing a simple modification to the traditional continuous modulation scheme (CMS) of differential inverters, which keeps the smooth operation of the grid-current control at the inverter side and verifies low execution time. Moreover, a detailed comparison between the proposed modulation scheme and traditional CMS at different power ratings is introduced. The performance of the proposed SVMS is evaluated using the PSIM environment to validate the theoretical features added to the grid-current control and the SEPIC-based differential inverter.