Natalia Ivanovna Sedova (Russian: Ната́лья Ива́новна Седо́ва; April 5, 1882, Romny – January 23, 1962, Corbeil) is best known as the second wife of Leon Trotsky, the Russian revolutionary. She was, however, also an active revolutionary in her own right and wrote on cultural matters pertaining to Marxism. Her father was Ivan Sedov, a famous explorer of the Arctic.
Her life was marked by the same tragedy as that of her lover, as she accompanied him into his final exile from Russia. Her son, Lev Sedov, was an active and leading member of the Bolshevik-Leninist movement that his father led and was almost certainly assassinated as a result of that. Her other son, Sergei Sedov, who was not politically active and remained in Russia, was almost certainly murdered by agents of Joseph Stalin.
After her husband's assassination in 1940, Natalia Sedova remained in Mexico and maintained contact with many exiled revolutionaries. Her best known work in these last years was a biography of Trotsky, which she co-authored with fellow Russian revolutionary Victor Serge. She was also close to the Spanish revolutionary Grandizo Munis who had led the tiny Spanish Sección Bolchevique-Leninista during the revolutionary events in the 1930s. Under his influence, she came to adopt the position that the USSR was a state capitalist society and that the Fourth International founded by Trotsky no longer held to the revolutionary programme of Communism. Therefore, she broke from the FI in 1951.