Abstract Cyclic voltammetry (CV) and square wave voltammetry (SWV) were used for characterizing and determining Gallic acid concentration in groundnut. In this study, Gallic acid (GA) content in groundnut was determined by SWV technique. The effect of Gallic acid concentration on the oxidation response of Glycine modified carbon paste electrode (GMCPE) at pH of phosphate buffer solution were investigated by CV. Application of the electrode is optimized with common cyclic voltammetry and square-wave voltammetry system; the latter being recommended for quantification. The electrode is vigorous to common interferents, and yield precise determinations in real samples analysis, even at very low gallic acid concentrations. It was found that the anodic peak current of GA is directly related to the concentration and scan rate, whereas during pH optimization, the anodic peak current was increased with the pH value ranges 2 – 3. However, the peak current was found to decrease after pH 3.0. Hence, pH 3.0 is chosen as the optimum value for this work. On the other hand, the anodic peak potential is shifted to less positive as a function of pH values used. A calibration curve was obtained by the square wave voltammetry at GMCPE after square wave frequency, step potential, and square wave amplitude were optimized. The optimized parameters chosen for the whole work were a wave frequency of 20 HZ, a step potential of 6 mV, and wave amplitude of 25 mV, respectively. The limit of detection (LOD) and limit of quantification (LOQ) of the GMCPE with specific results are 1.53 x 10-8 M and 5.1 x 10-8 M, respectively. The recoveries ranging between 93.33 -99.42% were achieved indicating the method for the determination of gallic acid in real samples was more valid. Key words: Gallic acid; Square wave voltammetry; Groundnut; Modified electrode; Glycin