Grand Duchess Anastasia Nikolaevna of Russia (Russian: Анастасия Николаевна Романова, romanized: Anastasiya Nikolaevna Romanova; 18 June [O.S. 5 June] 1901 – 17 July 1918) was the youngest daughter of Tsar Nicholas II, the last sovereign of Imperial Russia, and his wife, Tsarina Alexandra Feodorovna.

Anastasia was killed with the other members of her immediate family in a cellar where they had been confined by the Bolsheviks following the October Revolution. (Although there is some uncertainty over whether the family was killed on July 16 or 17, 1918, most sources indicate that the executions took place on the latter day.) After the executions, several women outside Russia claimed her identity, making her the subject of periodic popular conjecture and publicity. Each claimed to have survived the execution and managed to escape from Russia, and some claimed to be heir to the Romanov fortune held in Swiss banks.

Perhaps the most famous of these claimants was a woman who called herself Anna Anderson—and whom critics alleged to be one Franziska Schanzkowska, a Pole—who married an American history professor, J.E. Manahan, in 1968 and lived her final years in Virginia, U.S., dying in 1984. In the years up to 1970 she sought to be established as the legal heir to the Romanov fortune, but in that year West German courts finally rejected her suit and awarded a remaining portion of the imperial fortune to the duchess of Mecklenberg. In the 1990s, genetic tests undertaken on tissues from Anderson and on the exhumed remains of the royal family established no connection between her and the Romanovs and instead supported her identification with Schanzkowska. The remains of Anastasia and other members of the royal family had been located by Russian scientists in 1976, but the discovery was kept secret until after the collapse of the Soviet Union. Genetic testing conducted on the remains concluded that the grand duchess was, in fact, killed with the rest of her family in 1918.