Nicolas-Thomas Baudin (February 17, 1754 - September 16, 1803) was a French explorer.

Baudin was born on the Ile de Ré. At the age of fifteen he joined the merchant navy, and at twenty joined the French East India Company. He then joined the French navy and served in the Caribbean during the American War of Independence. After the war he captained ships transporting Austrian botanists to the Indian Ocean and the Pacific. During this time Baudin learnt about botany and how to keep plants and animals alive on board ship.

In 1792 France declared war on Austria and Baudin tried unsuccessfully to rejoin the French navy. He returned to France in 1795 and visited Antoine de Jussieu at the Museum National d'Histoire Naturelle to suggest a botanical voyage to the Caribbean. This voyage was a success, and Baudin returned to France with a large collection of plants, birds and insects.

In October 1800 he was selected to lead an expedition to map the coast of Australia. He had two ships, Le Géographe and Le Naturaliste, and was accompanied by nine zoologists and botanists, including Jean Baptiste Leschenault de la Tour. He reached Australia in May 1801, and in April 1802 met Matthew Flinders, also engaged in charting the coastline, in Encounter Bay. Baudin then stopped at the British colony at Sydney for supplies, then in Tasmania, before continuing north to Timor.

Baudin then sailed for home, stopping at Mauritius, where he died of tuberculosis.