Ludwig Christian Alexander Karl Martens (or Ludwig Karlovich Martens; Russian: Людвиг Карлович Мартенс; 1 January [O.S. 20 December] 1875 − 19 October 1948) was a Russian revolutionary, Soviet politician and engineer.
Ludwig Martens was born on 1 January 1875 n.s. in Bachmut, Ukraine, then part of the Russian empire. Ludwig's father, a German-born industrialist named Karl Gustav Adolf Martens, was the owner of a steel mill in Kursk, Russia. There were five sons and two daughters in the family. Two of them, Ludwig and Olga, became professional revolutionaries.
In 1893 Martens graduated from a Kursk Realschule and entered Saint Petersburg State Institute of Technology, from which he graduated to become a mechanical engineer.
While at the State Institute of Technology, Martens became acquainted Vladimir Lenin and Julius Martov. Soon he became a member of an illegal Marxist group League of Struggle for the Emancipation of the Working Class.
In 1896 he was arrested, and in 1899 as a German national was deported to Germany where he became a member of the Social Democratic Party of Germany. In 1902 he graduated from the Technical College of Charlottenburg. In 1906, following the failure of the 1905 Russian Revolution, Martens emigrated to Great Britain.