This paper proposes a sensorless control based on Sliding Mode Observer (SMO) for a Five-phase Interior Permanent Magnet Synchronous Machine (FIPMSM), with a consideration of the third harmonic component. Compared to the conventional three-phase machines, the third harmonic of electromotive force contains more information. Thus, in this paper, we consider the first and third harmonic components of the five-phase machine to estimate the rotor position that is necessary for the control. Simulation results of the implemented SMO are shown to verify the feasibility of the proposed sensorless control strategy