Faina Yefimovna Kaplan (Фаина Ефимовна Каплан; 1883–September 3, 1918), also known as Fanny Kaplan and as Dora Kaplan), was a Jewish political revolutionary and an attempted assassin of Vladimir Lenin.

There is a confusion as to her born name. Vera Figner in her memoirs, At Women's Katorga gives the name Feiga Chaimovna Roytblat-Kaplan Фейга Хаимовна Ройтблат-Каплан. Other sources give her original family name as Ройтман (transcribed from Russian as Roytman, which corresponds to the common German/Yiddish name Reutemann). However, her ties to Sidney Riley a British Intelligence officer had only deepened the mystery concerning her background

Kaplan was born into a Jewish family, one of seven children. She became a political revolutionary at an early age and joined a socialist group, the Socialist Revolutionaries (Esers). In 1906 Kaplan was arrested in Kiev after an accidental explosion of terrorist bombs she transported, and sentenced to life of katorga works. She served in Maltsev and Akatuy prisons, of Nerchinsk katorga, Siberia, where she lost her sight (partially restored later). She was released on March 3, 1917 after the February Revolution overthrew the imperial government. As a result of her imprisonment, Kaplan suffered from continuous headaches and periods of blindness.

Kaplan became disillusioned with Lenin as a result of the conflict between the Socialist Revolutionaries and the Bolshevik party. The Bolsheviks had strong support in the soviets, which Lenin had argued in his 1917 tract "The State and Revolution" were the only legitimate avenue of post-revolutionary government; however, in elections to a competing body, the Constituent Assembly, the Bolsheviks failed to win a majority in the November 1917 elections and a Socialist Revolutionary was elected President in January 1918. The Bolsheviks, favoring soviets, ordered the Constituent Assembly to be dissolved. Over the next few months conflicts between the Bolsheviks and their political opponents led to the banning of all parties except the Bolsheviks. Kaplan decided to assassinate Lenin.

By the official accounts, on August 30, 1918, Lenin was speaking at a Moscow factory. As Lenin left the building and before he entered his car, Kaplan called out to him. When Lenin turned towards her, she fired three shots. One passed through Lenin's coat, the other two hit him in the left shoulder and left lung.

Lenin was taken back to his living quarters at the Kremlin. He feared there might be other plotters planning to kill him and refused to leave the security of the Kremlin to seek medical attention. Doctors were brought in to treat him but were unable to remove the bullets outside of a hospital. But despite the severity of his injuries, Lenin survived. However, Lenin's health never fully recovered from the attack and it is believed the shooting contributed to the strokes that incapacitated and later killed him.

Kaplan was taken into custody and interrogated by the Cheka. She made the following statement: My name is Fanya Kaplan. Today I shot at Lenin. I did it on my own. I will not say whom I obtained my revolver. I will give no details. I had resolved to kill Lenin long ago. I consider him a traitor to the Revolution. I was exiled to Akatui for participating in an assassination attempt against a Tsarist official in Kiev. I spent eleven years at hard labour. After the Revolution I was freed. I favoured the Constituent Assembly and am still for it. When it became clear that Kaplan would not implicate other political opponents of Lenin, she was shot on September 3.

In recent years the actual role of Kaplan in assassination has been questioned. In particular, it is suggested that she was on secondary payroles and after the arrest she took the guilt upon herself. The main argument put forth in this and other versions is her near-blindness. Still another argument is the contradiction between the official Lenin's hagiography (Kaplan was immediately seized by angry workers who witnessed the event) and official documents, in particular a radiogram by Yakov Peters which talks about an arrest of several suspects.

She freely admitted to her sole role in the assassination attempt in a letter to "Mika", a man who was to give this letter (Yakov Peters) was convicted and executed by the NKVD in 1938. In her letter she states:

They send one after another of their lackeys to pry information from me. They do not believe that I was capable of acting alone. Perhaps you also cannot believe this? But it is true. Before this letter reaches you, you will have read in the newspapers that I shot at Lenin. I do not think I succeeded in killing him. If I regret anything, it is only that. He is a traitor to the Revolution. I lay the responsibility for the treacherous peace with Germany and the dissolution of the Constituent Assembly at his feet. I have told my inquisitors as much and so expect that they will not censor it from this letter. That this letter reaches you at all I have entrusted to Yakov Peters.

In the official announcement she was declared Right Eser. On August 17, only days before the attempted assassination of Lenin, Moisei Uritsky, People's Commissar for Internal Affairs in the Northern Region and head of the Cheka in Petrograd was assassinated. While there was no objective evidence linking the two assassinations, the Bolsheviks used them as an excuse to eliminate their political opponents.

An official decree for Red Terror was issued only hours after the Kaplan's shootings calling for "a merciless mass terror against all the enemies of the revolution". In the next few months, about 800 Right SRs and other political opponents of Bolsheviks were executed without trial. During the first year the scope of Red Terror significantly expanded and the executions counted by thousands even by official statistics. Some historians consider this to be a harbinger of the Great Purge, but others consider that the purges of the 1930s and the Great Terror were not only quantitatively different from the Red Terror under Lenin, but also took place for very different reasons and in a very different context.