This work presents the design and construction of a smart energy theft detector on distribution lines. The escalating challenge of power theft within distribution lines necessitates innovative solutions to safeguard the integrity of power distribution networks. Atmega328-P, Arduino-uno Micro-processor was interphase with Bluetooth module to detect energy theft. Proteus professional software was deployed to determine the functionality of the smart energy theft detector. The work was tested and the result obtained showed a stand-alone system capable of detecting energy theft on different phases of the distribution network. The information sent to the utility operator’s liquid crystal display (LCD) indicates theft detected on either red, blue or yellow phase.