I provide a new behavioral foundation for Cobb-Douglas preferences drawing on the psychophysical regularity known as Weber’s law. In particular, I show that, under Weber’s law, Cobb-Douglas preferences are characterized by two novel and compelling axioms. Importantly, the preferences that I characterize are the standard (weak-ordered and strongly monotonic) Cobb-Douglas preferences widely used in consumer theory, thereby complementing prior literature that has instead obtained a semi-ordered and non-monotonic variant thereof.