Light scattering is an intrinsic property of colloidal nanoparticles and molecular assemblies in fluid or solid transparent media. Various measurable light scattering parameters may contribute to the characterization of colloidal systems. Herein, a quantitative, spectrallyresolved, steady-state light scattering technique is formulated and realized for the characterization of ensembles of colloidal nanoparticles in solution: quantum-efficiency normalized light scattering (QENLS) spectroscopy. QENLS spectra are complementary to standard ultraviolet-visible-near-infrared (UV-vis-NIR extinction spectra. Their measurement does not require knowledge of nanoparticle concentration, and they can be quantitatively compared to theoretical calculations. This is illustrated for archetypal plasmonic gold nanospheres, nanocubes and nanorods. We find good agreement between experimental and theoretical QENLS spectra for gold nanospheres and nanocubes, corroborated by results from the literature. Concerning gold nanorods, our QENLS results fall into the broad, somewhat disperse trends reported in the literature.