A country's exchange rate regime under which the government or central bank ties the official exchange rate to another country's currency (or the price of gold). The purpose of a fixed exchange rate system is to maintain a country's currency value within a very narrow band. Also known as pegged exchange rate.

There are benefits and risks to using a fixed exchange rate. A fixed exchange rate is usually used in order to stabilize the value of a currency by directly fixing its value in a predetermined ratio to a different, more stable or more internationally prevalent currency (or currencies), to which the value is pegged. In doing so, the exchange rate between the currency and its peg does not change based on market conditions, the way floating currencies will do. This makes trade and investments between the two currency areas easier and more predictable, and is especially useful for small economies in which external trade forms a large part of their GDP (Gross Domestic Product).

Fixed rates provide greater certainty for exporters and importers. This also helps the government maintain low inflation, which in the long run should keep interest rates down and stimulate increased trade and investment. However in doing so, the pegged currency is then controlled by its reference value. As such, when the reference value rises or falls, it then follows that the value(s) of any currencies pegged to it will also rise and fall in relation to other currencies and commodities with which the pegged currency can be traded. In other words, a pegged currency is dependent on its reference value to dictate how its current worth is defined at any given time. In addition, according to the Mundell–Fleming model, with perfect capital mobility, a fixed exchange rate prevents a government from using domestic monetary policy in order to achieve macroeconomic stability.

In a fixed exchange-rate system, a country’s central bank typically uses an open market mechanism and is committed at all times to buy and/or sell its currency at a fixed price in order to maintain its pegged ratio and, hence, the stable value of its currency in relation to the reference to which it is pegged. The central bank provides the assets and/or the foreign currency or currencies which are needed in order to finance any payments imbalances.

In the 21st century, the currencies associated with large economies typically do not fix or peg exchange rates to other currencies. The last large economy to use a fixed exchange rate system was the People's Republic of China which, in July of 2005, adopted a slightly more flexible exchange rate system called a managed exchange rate. The European Exchange Rate Mechanism is also used on a temporary basis to establish a final conversion rate against the Euro (€) from the local currencies of countries joining the Eurozone.