Systems and methods for path length selected diffuse correlation spectroscopy (PLS-DCS) are disclosed. The systems and methods are suitable for measuring dynamics of a target medium. The systems and methods can utilize light sources having a coherence length that is shorter than a path length distribution of the target medium and can utilize a reference optical path to interferometrically detect PLS-DCS signals. The coherence length and reference path length can be selected to provide sensitivity to portions of the target medium that correspond to a desired path length distribution.