In this paper, interval type-2 fuzzy logic controller based maximum power point tracking method is proposed for photovoltaic systems. The proposed interval type-2 fuzzy logic controller has two inputs and one output. Rate of change in photovoltaic system output power and rate of change in photovoltaic system terminal voltage are selected as input variables and change in duty cycle as output variable. Seven type-2 membership functions are used for determined input and output variables of fuzzy logic controller. Since type-2 fuzzy sets are used, effect of uncertainties on maximum power point tracking capability is removed. Operation point of the photovoltaic system is controlled via a boost type DC-DC converter. Simulation results show that the proposed maximum power point tracking method provides fast dynamic response, and it is also useful for rapidly changing atmospheric conditions.