The political economy of exchange rates is a scholarly field of study that examines why governments adjust the value of their currencies, choose to have the exchange rate fix or float in its value, or agree or disagree on international rules for the exchange rate. Modern research on this field of study began in the 1970s and has developed several theories to examine these questions over the past decades. Economic theories of exchange rate regimes frequently cite three economic models, the Mundell-Fleming model, optimal currency area theory, and the time-inconsistency problem. International relations theories have focused on the global political economy of regimes, including the role of hegemonic leadership in shaping regimes and resolving disputes, the role of interstate negotiation in the formation and maintenance of regimes. The analysis of negotiation saw contributions from three major traditions of international relations theory: neo-liberalism, realism, and constructivism. Research into second major topic, domestic exchange rate regimes, examines how governments make these decisions. During the 1990s, recognition that governments’ de jure commitment to fixed, floating, or other form of exchange rate did not necessarily correspond to actual practice initiated a new round of research. Scholarly engagements with this puzzle include optimal currency area theory, national interest-based approaches, and national identity-based approaches. There has also been scholarship on the conundrum of de jure v. de facto exchange rate regimes. Another area of research, exchange rate valuation, breaks down into sectoral interest-group approaches focused on production and finance, institutional approaches focused on elections and central bank independence, and some ideational approaches focused on economic and political ideology. Anticipated areas of future research include further development of the political economy of exchange rate valuation regimes; inquiry into the interaction of the spread of populist nationalist movements and exchange rates, leading possibly to more mercantilist valuation policies; and investigation of the length of time governments choose to fix or float their exchange rates.