A structural health monitoring system and method uses a resonant transmission line sensor. A resonant transmission line sensor, which includes one or more sensor conductors and a dielectric material disposed at least proximate the one or more sensor conductors, is coupled to the structure. The dielectric material exhibits a dielectric constant that varies when at least a portion of the transmission line sensor is subjected to one or more stimuli. One or more resonant frequencies of the transmission line sensor are determined, and the determined one or more resonant frequencies are then correlated to the structural health of the structure.