Managing impedance in coaxial cable termination. In one example embodiment, a method for terminating a coaxial cable is provided. The coaxial cable includes an inner conductor, an insulating layer surrounding the inner conductor, an outer conductor surrounding the insulating layer, and a jacket surrounding the outer conductor. The method includes various acts. First, a section of the insulating layer is cored out. Next, the diameter of the inner conductor that is positioned within the cored-out section is reduced. Then, at least a portion of an internal connector structure is inserted into the cored-out section so as to surround the section of reduced-diameter inner conductor. Finally, an external connector structure is affixed to the internal connector structure. A coaxial cable termination tool for use in the termination of a coaxial cable and a terminated coaxial cable are also disclosed.