Thomas Dyke Acland Tellefsen (November 26, 1823–October 6, 1874) was a Norwegian pianist and composer. As a composer Tellefsen wrote 44 opuses:[1] solo piano works, two piano concertos, and chamber music. He dedicated many of his compositions to the Polish, Russian, and French aristocracy.
Thomas Tellefsen, the youngest of six siblings,[1] was born in Trondheim, Norway, where he studied with his father, the organist Johan Christian Tellefsen (1774–1857), and with Ole Andreas Lindeman.[2] Thomas gave his first public concert in his home town in the spring of 1842. Shortly after, he went to Paris, where he became the pupil of his compatriot Charlotte Thygeson, and later attended some of Friedrich Kalkbrenner's classes. During the years 1844 to 1847, he was taught periodically by Frédéric Chopin, who also became his personal friend and had considerable influence on his musical taste, style of playing, and compositions.

Duchess Marcelina Czartoryska took him to the Hôtel Lambert in Paris, where he made his debut as a pianist with great success on 29 April 1851.[3] Soon after that, Tellefsen became regarded as one of the outstanding pianists of his time, and was especially admired as an interpreter of Chopin's music. When Chopin died in 1849, Tellefsen took over some of his teacher's pupils, including Jane Stirling.[3] In the 1850s and 1860s, Tellefsen was regarded as a very successful pianist, and he toured several times in England, Sweden, and Norway. He died in Paris, and is buried at the Cimetière d´Auteuil.