One of the key challenges for inflationary model builders is to explain how inflation ends. When inflation ends, all but the very smallest comoving scales lie outside the horizon, and almost any conceivable relic generated during this period is unlikely to survive to the present epoch. However, I show that many scenarios for ending inflation (particularly parametric resonance, preheating and bubble nucleation) can source a significant stochastic background of gravitational waves. I discuss the ways in which the frequency and amplitude of this signal depend on inflationary physics, its detectability by current and future gravitational wave observatories, and the distinction between this signal and the cosmological gravitational wave background generated during inflation.