Abstract—A multilevel boost converter (MLBC) with fractional order- proportional integral (FO-PI)-based perturb and observe (P&O) maximum power point tracking (MPPT) controller is proposed to enhance the performance of photovoltaic (PV) systems. Two control schemes for the MLBC were investigated: i) MLBC with FO-PI-based P&O MPPT controller and ii) MLBC with only P&O MPPT controller. The simulation results, carried out using MATLAB/SIMULINK package, show that the performance of the MLBC with FO-PI-based P&O MPPT controller much over weights that of the MLBC with only P&O MPPT controller in terms of rise time, peak overshoot and settling time. These results indicate that the proposed system constitutes a good candidate for implementation in PV applications, in order to extract maximum electric power and to supply high output voltage to the load.