Extremal black holes exhibit qualitatively different behaviour to sub-extremal black holes - for example, typical decay rates for perturbations are polynomial in time, rather than exponential. For a sub-extremal black hole, information about the late time response to perturbations is encoded in the quasinormal spectrum. In this talk I will discuss the behaviour of the quasinormal spectrum in the approach to extremality. (Joint work with Dejan Gajic).