Ulrik Anton Motzfeldt (27 January 1807 – 10 July 1865) was a Norwegian jurist and politician. He served five terms in the Norwegian Parliament, including two years as President. He was also a professor in Christiania and an Assessor of the Supreme Court.
Ulrik Anton Motzfeldt was born on the island St. Thomas, then a part of the Danish West Indies. His father, Peter Motzfeldt was a noted military officer and father of the Norwegian Constitution who was stationed on St. Thomas from 1802 to 1809, Ulrik's mother, Erneste Birgitte Margrethe, was the daughter of the B. C. Stenersen, stipendiary magistrate of St. Thomas. Ulrik's younger brother Ketil was also a noted statesman. In addition, their paternal great-grandmother Birgitte Andrea Bull was a first cousin of Johan Lausen Bull and Norway's first Supreme Court Justice Johan Randulf Bull.
Ulrik Anton Motzfeldt married twice. The marriage with his first wife produced two daughters. Their daughter Marie Sophie Erneste married jurist and politician Ulrik Fredrik Christian Arneberg. Motzfeldt later married Anna Pauline Jørgine Birch, and the couple had two sons and one daughter. Their oldest son Ernst became a government minister.
Ulrik Anton Motzfeldt enrolled as a law student in 1823, and graduated with the cand.jur. degree in 1826. In 1829 he was hired as a lector at the Royal Frederick University (now University of Oslo). He was promoted in 1834, to professor of jurisprudence. His most important publications include Den norske Kirkeret (1844) and Lovgivningen om Odelsretten og Aasædesretten (1846). From 1842 Ulrik Anton Motzfeldt also served as a Supreme Court Assessor.