This entry provides a comprehensive basis for readers to grasp recent research progresses on electrical behaviors of Carbon fiber reinforced polymer (CFRP), which plays an important role in many fields, especially in aviation and civil industries. The electrical conductivity of CFRP is critical for its electrical behaviors, such as its lightning strike vulnerability, electromagnetic shielding ability, and potential uses for self-sensing. In addition, the electrical conductivity is related to the mechanical integrity. Therefore, electrical properties can be measured as an indication in the detection of delamination and other defects in CFRP.