We present a new data fact: in response to a monetary tightening, the nominal exchange tends to appreciate in developed countries but depreciate in developing countries. A model is formalized to rationalize this contrasting pattern. It has three key channels of monetary transmission: a liquidity demand channel, a …scal channel and an output channel. These have o¤setting e¤ects on the exchange rate.The paper shows that a calibrated version of the model can explain the contrast between developed and developing countries. Using counterfactual experiments we identify di¤erences in the liquidity demand e¤ect as being key to the contrasting responses generated by the model. Finally, the paper provides independent evidence of systematic variation between appreciating and depreciating countries in the strength of the liquidity demand e¤ect.JEL Classi…cation: F3, F4