Tharangambadi (formerly Tranquebar) is a panchayat town in Nagapattinam district in the Indian state of Tamil Nadu, 15 km north of Karaikal, near the mouth of a distributary of the Kaveri River. Tharangambadi is the headquarters of Tharangambadi taluk. Its name means "place of the singing waves". It was a Danish colony from 1620 to 1845, and in Danish it is still known as Trankebar.

Tharangambadi is located at 11°02′N 79°50′E / 11.03°N 79.84°E / 11.03; 79.84.

The earliest reference to Tarangampadi occurs in a 14th century inscription, mentioning the place as Sadanganpade. Tranquebar was founded by the Danish East India Company in 1620, when a factory (commercial settlement) was opened and a fort, known as Fort Dansborg, was built by a Danish captain named Ove Gjedde. This fort was the residence and headquarters of the governor and other officials for about 150 years. It is now a museum hosting a collection of artifacts from the colonial era.

Among the first Protestant missionaries to set foot in India were two Lutherans from Germany, Bartholomäus Ziegenbalg and Heinrich Pluetschau, who began work in 1705 in the Danish settlement of Tranquebar. They translated the Bible into the local Tamil language, and afterwards into Hindustani. They also established a printing press, which within a hundred years of its establishment in 1712 had printed 300 books in Tamil. At first they only made little progress in their religious efforts, but gradually the mission spread to Madras, Cuddalore and Tanjore. Today bishop of Tranquebar is the official title of a bishop in the Tamil Evangelical Lutheran Church (TELC) in South India which was founded in 1919 as a result of the German Lutheran Leipzig Mission and Church of Sweden Mission. The seat of the Bishop, the Cathedral and its Church House ("Tranquebar House") is in Tiruchirappalli.