Mercator (Latin for "merchant") may refer to:
- Marius Mercator (c. 390–451), a Catholic ecclesiastical writer
- Gerardus Mercator, a 16th-century Flemish cartographer
- Mercator projection, a cartographic projection devised by Gerardus Mercator
- Nicholas Mercator, a 17th-century mathematician
- Mercator Telescope, a Flemish telescope installed in La Palma, Canary Islands
- Mercator (retail), a Slovenian supermarket chain
- Mercator (ship), a barquentine museum ship in Oostende, Belgium
- P4M Mercator, a reconnaissance aircraft used by the United States Navy during the 1950s
- QinetiQ Mercator, a British unmanned aerial vehicle (UAV)
- Mercator School of Management, University of Duisburg-Essen, Germany
- Mercator Limited, Shipping company in India
- Mercator Corporation, a consulting firm and investment bank formed by James Giffen, involved with Kazakhgate
- Mercator K55K, a type of pocketknife produced in Germany
- SS Mercator and MV Mercator, a number of ships named Mercator
- Mercator (play), a comedic play by Plautus
- Mercator network, a network of universities active in research on lesser-used languages in Europe