Martín García Island (Spanish: Isla Martín García) is an Argentine island off the Río de la Plata coast of Uruguay. The Argentine exclave island is within the boundaries of Uruguayan waters; in 1973 both countries reached an agreement establishing Martín García as an Argentine territory and also as a nature reserve.

The island of 1.84 km² (0.7 sq mi) has a permanent population of about 150 people (50 families), and belongs to the Buenos Aires Province.

The strategically located island was the site of a fortification built in the 1820s by Argentine forces to deny the Brazilian navy access to the Uruguay River. This fort, named Constitucion, succeeded in keeping Brazilian reinforcements at bay during the Battle of Juncal between 8 and 9 February 1827, allowing the Argentines to destroy the Brazilian squadron operating on the Uruguay River during the Cisplatine War. In more modern times, several Argentine political figures were kept in the island under arrest by different military governments, including Presidents Hipólito Yrigoyen (1930), Juan Perón (1945), and Arturo Frondizi (1962).

Martín Alberto García (born 2 May 1977, in Buenos Aires) is a professional tennis player from Argentina.

García turned pro in 1996, and has won 7 doubles titles on the ATP Tour during his career. He reached his career high doubles ranking of World No. 21 on May 21, 2001.