In this work, a quantitative study for glucose concentration determination was conducted using ATR-THz spectroscopy. Glucose solutions with different concentrations were prepared and their absorbance spectra between wavenumber 19.285 cm^-1 and 451.261 cm^-1 were acquired using a terahertz-based Fourier transform spectrometer. The spectra of glucose solutions in different concentrations were compared and discussed. The results showed that increasing glucose concentration caused decreasing absorbance. Calibration models for glucose determination were developed using partial least squares (PLS) regression for original and pre-processing spectra. The calibration model using Savitzky-Golay second derivative spectra gave satisfactory results. The use of ATR-THz spectroscopy combined with an appropriate chemometric method has potential for a rapid determination of glucose concentrations in aqueous solution.