The chapter summarizes research results on temperature evolution of optical absorption spectra in a wide temperature range of 6.5–296 K for colloidal core/shell InP/ZnS quantum dot ensembles with a different size distribution. Exciton–optical transition energies in the InP core and ZnS shell were determined by the second-order derivative spectrophotometry. Numerical analysis within the frame of linear exciton–phonon coupling showed that the shifts of the observed spectral maxima with temperature were due to the interaction of excited states with longitudinal acoustic vibrations. It was established that the half-width of the spectral bands remained unchanged, which indicated the inhomogeneous broadening effect and a high degree of static disorder in the ensembles under study. The semi-phenomenological model was proposed that took into account the effects of the exciton–phonon interaction and allowed one to analyze the influence of the static and dynamic types of atomic disorder on behavior of optical absorption spectra in InP/ZnS quantum dots under temperature variation.