We present the main parameters, design features, and optical characterization of the Granada Sprite Spectrograph and Polarimeter (GRASSP), a ground-based spectrographic system intended for the analysis of the spectroscopic signature of transient luminous events (TLEs) occurring in the mesosphere of the Earth. It has been designed to measure the spectra of the light emitted from TLEs with a mean spectral resolution of 0.235 nm and 0.07 nm/px dispersion in the wavelength range between 700 and 800 nm.