I will discuss applications of effective field theories to black holes. I will first review the derivation of an effective theory for the perturbations of black holes in the context of scalar-tensor theories and its application to the study of their spectrum of quasi-normal modes. I will introduce a novel analytical approach to estimate the quasi-normal frequencies, which generalizes the well-known WKB approach by Schutz and Will to cases where the equations for the perturbations are coupled. I will then discuss the symmetries that are responsible for the vanishing of the Love number couplings (i.e., the coefficients of the conservative static tidal response) in the point-particle effective theory of black holes in general relativity.