Anna Ivanovna Abrikosova (Russian: Анна Ивановна Абрикосова) (later known as Mother Catherine of Siena, O.P.) (Russian: Екатери́на Сие́нская or Ekaterina Sienskaya), (23 January 1882, Kitaigorod, Moscow, Russian Empire – 23 July 1936, Butyrka Prison, Moscow, Soviet Union) was a prominent figure in the Russian Catholic Church, and the foundress of a community of Religious Sisters of the Third Order of St. Dominic in that Church.
Since 2002, her life has been under scrutiny for possible beatification by the Holy See. Her current title is Servant of God.
Anna Ivanovna Abrikosova was born into a merchant family, the official suppliers of chocolate confections to the Russian Imperial Court. Although the younger members of the family rarely attended Divine Liturgy, the Abrikosovs regarded themselves as pillars of the Russian Orthodox Church. Anna's parents died early: her mother while giving birth to her, and her father ten days later, of tuberculosis. Anna and her four brothers were raised in the house of her uncle, Nikolai Alekseevich Abrikosov. She graduated from gymnasium in Moscow and Girton College, Cambridge. In 1903, she returned to Russia and married her first cousin, Vladimir Abrikosov. Most of the next ten years, they spent traveling in the Kingdom of Italy, Switzerland and France.