Countess Ana Katarina Zrinska (c. 1625–1673) was a Croatian noblewoman and poet, born into the House of Frankopan, a Croatian noble family. She married Count Petar Zrinski of the House of Zrinski in 1641 and later became known as Katarina Zrinska. She is remembered in Croatia as a patron of the arts, a writer and patriot. She died in obscurity in a monastery in Graz following the downfall of the Zrinski-Frankopan conspiracy in 1671 and the execution of both her husband Petar Zrinski and her brother Fran Krsto Frankopan. Her most notable literary work is Putni tovaruš, written 1660 at her estates in Ozalj.

Katarina Zrinski and the conspiracy were largely forgotten until the 1860s, when Croatian politician Ante Starčević began a campaign to rehabilitate the Zrinski and Frankopan nobility, and the story of her life and death was widely popularised following the publishing of Eugen Kumičić's historical novel Urota Zrinsko-Frankopanska (English: The Zrinski-Frankopan Conspiracy) in 1893.

In the early 20th century, and especially after World War I, numerous Croatian women's associations were founded bearing her name. In 1999 the Croatian National Bank issued a silver commemorative coin depicting Katarina Zrinski, in their Znamenite Hrvatice (English: Famous Croatian Women) series, along with children's writer Ivana Brlić-Mažuranić and painter Slava Raškaj.

Katarina was born in Bosiljevo near the modern city of Karlovac in present-day Croatia to Vuk Krsto Frankopan of the House of Frankopan, a well-known commander (general) and nobleman in the Croatian Military Frontier (which was an autonomous region carved out of the Kingdom of Croatia within the Austrian Empire) and his second wife Uršula Inhofer. Fran Krsto Frankopan, also a notable nobleman, was her half brother, produced in Vuk Krsto's third marriage to Dora Haller.

She was homeschooled in her youth, and learned German during her childhood years (as it was her mother's first language) along with Hungarian, Latin and Italian which she was later taught. In 1641 she married the Croatian nobleman Petar Zrinski in Karlovac, who later went on to become Ban (viceroy) of Croatia following his brother Nikola Zrinski's death in 1664. After marrying Petar the pair spent most of their time at Ozalj Castle, the family residence.

In 1660 she wrote a prayer book titled Putni tovaruš, and had it printed in 1661 in the Republic of Venice before presenting it as a gift to the 17th century Croatian lexicographer Ivan Belostenec (the book was later re-printed in 1687 and 1715 in Ljubljana and then again in 2005 in Čakovec).

Katarina and Petar had four children, born between 1643 and 1658:

Known as Jelena Zrinska in Croatia and Ilona Zrínyi in Hungary, she married Hungarian nobleman Francis I Rákóczi in 1666. After his death in 1676, she married her second husband Imre Thököly, a Hungarian statesman and Prince of Transylvania, in 1682. She was also mother to Francis II Rákóczi, leader of the Hungarian uprising against the Habsburgs in the early 18th century.