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A photoelectrochemical sensor for dopamine was fabricated by the immobilization of bismuth vanadate (BiVO₄) and graphene quantum dots on a fluorine-doped tin oxide (FTO) glass electrode. Electrochemical impedance spectroscopy experiments demonstrated that the presence of graphene quantum dots contributed to the decrease in charge transfer resistance of the sensor under irradiation of visible light in the presence of dopamine. The photocurrent signals obtained were proportional to the dopamine concentration from 3.6 × 10⁻⁸ to 2.5 × 10⁻⁴ mol L⁻¹, with a detection limit estimated at 8.2 × 10⁻⁹ mol L⁻¹ and a limit of quantification at 2.7 × 10⁻⁸ mol L⁻¹.