The Freundlich adsorption isotherm is a useful description of adsorption phenomena. It is frequently presented as an empirical equation with little theoretical basis. In fact, a variety of derivations exist. Here a new derivation is presented using the concepts of fractal reaction kinetics. This derivation provides an alternative basis for interpreting the parameters obtained using the Freundlich isotherm. The derivation is simple enough to be used in an undergraduate chemistry class. The derivation can also be extended to a fractal-like Langmuir adsorption isotherm.