A graphene-based carbon ionic liquid electrode modified with gold nanoparticles was fabricated. The electrochemical response of the modified electrode toward celecoxib was studied by means of cyclic voltammetry and differential pulse voltammetry. The structural morphology of the modified electrode was characterized by a scanning electron microscopy technique and electrochemical impedance spectroscopy. The prepared electrode showed excellent electrocatalytic activity in the reduction of celecoxib in a phosphate buffer solution, leading to remarkable enhancements in the corresponding peak currents and lowering of the peak potential. The advantages are related to the unique properties of graphene and gold nanoparticles such as a large surface area and increased electron-transfer abilities. Differential pulse voltammetry was applied to the quantitative determination. The calibration curve was linear in the concentration range of 0.5 to 15 μM and the detection limit was about 0.2 μM (Sb/N = 3). The proposed electrochemical sensor was successfully applied to the determination of celecoxib in real samples.