A liquid injection thrust vector control (LITVC) system was designed for a hybrid rocket that uses 95 wt % hydrogen peroxide, and the system was demonstrated by using the hydrogen peroxide as the injectant. The influence of the chamber pressure, injectant flow rate, and injection location on the LITVC performance was parametrically investigated. The investigations revealed that the chamber pressure had a significant influence on the LITVC performance. As the chamber pressure increased from 20 to 40 bar, the side specific impulse improved from 71.7 to 157.3 s under injectant flow rates equal to 9% of the primary gas flow rates and at the injection location of X/L=0.47 (where X is the distance from the throat to the injection location and L is the length of the nozzle diverging section). To examine the effects of injection location on the LITVC performance, side specific impulses were measured at X/L=0.3, 0.47, and 0.72 under the chamber pressure condition of 40 bar. Among all injection locations, X/L=0.47 provided the highest side specific impulses under all injectant flow rate conditions. Furthermore, the radial spreading caused by increasing the injectant flow rates degraded the LITVC efficiency.