A modified glassy carbon (GC) electrode coated with an organic molecule 1H-1,2,4-triazole-3-thiol (T3T) was prepared for the selective and sensitive phenol (Ph) determination. The modified electrode (T3T-GC) was characterised using some electrochemical and spectroscopic techniques. The functional groups of T3T were determined on the GC surface by Fourier transform infrared spectroscopy (FTIR). The electro-oxidation behaviour of Ph was investigated on the modified electrode by differential pulse voltammetry (DPV) in 0.1 M phosphate buffer of pH 6.5. The calibration curve for Ph showed two linear ranges from 0.088 to 10.7 mu M (R-2 = 0.9966) and from 10.7 to 68 mu M (R-2 = 0.9969). The detection limit of Ph at the T3T-GC electrode was 25.8 nM (3s/m). The repeatability and reproducibility of the analysis with the relative standard deviations were calculated as 2.7% and 4.6%, respectively. The prepared electrode performance was assessed for Ph determination in tap water samples.