Karin Fossum is a Norwegian author of crime fiction, often referred to as the "Norwegian queen of crime".

Karin Ireland is an American author. Many of her books are self-help guides.

Karin Kallmaker is an American author of lesbian fiction whose works also include those originally written under the name Laura Adams. Her writings span lesbian romance, lesbian erotica, and lesbian science-fiction/fantasy. Dubbed the Queen of Lesbian Romance, she publishes exclusively in the lesbian market as a matter of personal choice.

Karin Muller is a Swiss-born author, filmmaker, photographer, and adventurer. She graduated from Williams College in 1987.

Karin Slaughter is an American crime writer. She has written 24 novels, which have sold more than 40 million copies and have been published in 120 countries. Her first novel, Blindsighted (2001), was published in 27 languages and made the Crime Writers' Association's Dagger Award shortlist for "Best Thriller Debut" of 2001.

Karin Smirnov or Smirnoff was a Finno-Swedish writer. She was the daughter of August Strindberg and Siri von Essen.

Karin Tabke is an American author. Born in Miami, Florida, United States she now lives in Northern California.

Karin Margareta Tidbeck is a Swedish author of fantasy and weird fiction.

Karin Wahlberg is a Swedish obstetrician and author. She is most famous for her crime series about Criminal Inspector Claes Claesson and his wife Veronika Lundborg, chief physician at Oskarshamn Hospital. In 2012 her authorship was introduced to America. Her work has been likened to the traditional detective fiction of Agatha Christie.

Karine Tuil, is a French novelist who has written several award-winning novels in French and English. Her works have themes ranging from marriage and Jewish identity to detention centers and corporate politics.