Caitlin (Irish pronunciation: [ˈkatʲlʲiːnʲ]) is a feminine given name of Irish origin. Historically, the Irish name Caitlín was anglicized as Cathleen or Kathleen. In the 1970s, however, non-Irish speakers began pronouncing the name according to English spelling rules as /ˈkeɪtlɪn/ KAYT-lin, which led to many variations in spelling such as Caitlin, Ceitlin, Catelynn, Caitlyn, Katlyn, Kaitlin, Kaitlyn, Katelyn and Katelynn.^[1][2][3]

It is the Irish version of the Old French name Cateline [katlin], which comes from Catherine, which in turn comes from the Ancient Greek Αἰκατερίνη (Aikaterine). Catherine is attributed to St. Catherine of Alexandria.^[4] Along with the many other variants of Catherine, it is generally believed to mean "pure" because of its long association with the Greek adjective καθαρός katharos (pure), though the name did not evolve from this word.^[5]

• Catelyn Stark, from the A Song of Ice and Fire book series and television series
• Caitlin, in the second season of the TV series Heroes
• Caitlin, in the Pokémon series; first introduced in the Sinnoh Battle Frontier, she was later revealed to be an Unova Elite Four member
• Caitlyn Kiramman, the Sheriff of Piltover, a playable champion character in video game League of Legends and character in the animated series Arcane
• Kait(lyn), in the webcomic Freakangels
• Caitlin Atkins, from Australian television series Neighbours
• Caitlin Bree, from 1994 movie Clerks
• Caitlin Cooke, from the show 6teen
• Kaitlin Cooper, from American television series The O.C.
• Caitlin Deschanel, from American television series Sunset Beach
• Caitlin Fairchild, from the comic Gen¹³
• Caitlyn Goodwyn, a.k.a. Pop Harukaze, from the Japanese anime series Ojamajo Doremi
• Caitlin Pike, from American television series JAG
• Caitlin Poythress, from the television series We Are Who We Are
• Caitlin Ramirez, from The Bold and the Beautiful
• Caitlin Ryan, from the Degrassi television series
• Caitlin Seeger, main character of the US-Canadian live action children’s drama Caitlin's Way
• Caitlin Snow (also known as Killer Frost) from the CW's The Flash
• Caitlin O'Shannessy, from the American television series Airwolf
• Caitlin Todd, from the American television series NCIS
• Caitlin the Streamlined engine, a recurring character in the television series Thomas & Friends

• Typhoon Caitlin (disambiguation), two tropical cyclones

• Cathleen
• Kathleen (disambiguation)
• Kathleen (given name)