A tool for separating components of a modular prosthesis includes an upper and lower body, each defining opposing bills at one end that are sized to fit in juxtaposed relation within an initial gap between the components. The upper body is provided with a handle so that the tool may be manually held by the surgeon with the opposing bills in position in the prosthesis. The tool includes a jack assembly disposed between the upper and lower bodies of the tool that is configured to be driven into an extended position, gradually separating the upper and lower bodies, and consequently exerting a separation force on the prosthesis components through the bills of the tool. The jack assembly is driven by a threaded actuator rod that bears against one element of the jack assembly as the actuator rod is rotated within a threaded bore in one of the bodies of the tool.