The ouguiya (sign: UM; Arabic: أوقية; currency code: MRO), also spelt "ougiya", is the currency of Mauritania. It is the only circulating currency other than the Malagasy ariary whose division units are not based on a power of ten, each ouguiya comprising five khoums (singular and plural in English, Arabic: خمس, meaning "one fifth").
The ouguiya was introduced in 1973, replacing the CFA franc at a rate of 1 ouguiya = 5 francs.