Quantum chaos describes the dynamics of a many-body system at the onset of thermalization, while hydrodynamics describes the late time dynamics after thermalization has occurred locally. Consistency between these two descriptions provides constraints linking hydrodynamic data such as diffusion constants and sound speeds to quantum chaos. This provides an intuitive explanation for recently observed connections between the butterfly velocity and diffusion constants in many strongly interacting systems. I will conclude by describing some of the subtleties that modify these constraints in various large N theories, along with non-trivial consistency checks of these constraints in Sachdev-Ye-Kitaev chains and in holographic models.