We present evidence that the funding liquidity of U.S. financial intermediaries forecast U.S. dollar exchange rate growth---at weekly, monthly, and quarterly horizons, both in-sample and out-of-sample, and against a large set of foreign currencies. We provide a theoretical foundation for a funding liquidity channel in a simple asset pricing model where the effective risk aversion of dollar-funded intermediaries fluctuates with the tightness of their risk constraints. We estimate prices of risk using a cross-sectional asset pricing approach and show that U.S. dollar funding liquidity forecasts exchange rates because of its association with time-varying risk premia. Our empirical evidence shows that this channel is separate from the more familiar "carry trade" channel.