An investigation was conducted in the Langley 16-Foot Transonic Tunnel (16FTT) to determine the multiaxis thrust vectoring characteristics of the F-18 high-alpha research vehicle (HARV). A 0.10-scale model of the F-18 airplane was modified with hardware to simulate the three-vane thrust vectoring system of the F-18/HARV. This investigation was conducted at Mach numbers ranging from 0.30 to 0.70, angles of attack from 0 to 70 deg, and nozzle pressure ratios from 2.0 to approximately 5.0. Results indicate that the thrust vectoring system of the F-18/HARV can generate useful levels of multiaxis thrust vectoring. During vectoring, resultant thrust vector angles were always less than the corresponding geometric vane deflection angle and were accompanied by large thrust losses. Significant external flow effects that were dependent on Mach number and angle of attack were noted during vectoring.