| Author (number of quotes) | Description |
| Ka |
| Kafka, Franz (2) | German author |
| Kahlo, Frida (3) | Mexican painter |
| Kahneman, Daniel (2) | Israeli-American psychologist |
| Kaku, Michio (5) | American theoretical physicist |
| Kambarangwe, Festo Michael (1) | |
| Kampen, Irene (1) | |
| Kanin, Garson (1) | American author and director |
| Kant, Immanuel (3) | German philosopher |
| Kate, Lauren (1) | American author |
| Kauffmann, Max (1) | |
| Kaufman, Josh (1) | american business expert, author |
| Kaulitz, Bill (1) | German singer, songwriter, fashion designer and model |
| Kaur, Rupi (4) | Indian-born Canadian poet, author, and illustrator |
| Kazantzakis, Nikos (1) | Greek novelist, poet, playwright and philosopher |
| Ke |
| Keats, John (2) | English poet |
| Kebbel, Arielle (1) | American actress, model and singer |
| Keen, Sam (1) | American author, professor and philosopher |
| Keeney, Gary (1) | |
| Keillor, Garrison (3) | |
| Keller, Helen (10) | American deafblind author, political activist, and lecturer |
| Kelley, Kitty (1) | American journalist |
| Kenison, Katrina (4) | American writer |
| Kennedy, John Fitzgerald (3) | the 35th President of the United States |
| Kennedy, Robert F. (1) | American politican |
| Kenyon, Sherrilyn (1) | American writer |
| Kepler, Johannes (3) | German mathematician, astronomer |
| Kerouac, Jack (2) | |
| Kerr, Walter (1) | |
| Kettering, Charles Franklin (1) | American scientist and philosopher |
| Key, Ellen (2) | |
| Keynes, John Maynard (2) | English mathematician, economist |
| Kh |
| Khalifa, Wiz (3) | stage name of Cameron Jibril Thomaz, American rapper |
| Ki |
| Kidd, Sue Monk (3) | American writer |
| Kidman, Nicole (2) | Australian actress and producer |
| Kilmer, Val (1) | American actor |
| King, B. B. (2) | stage name of Riley B. King, American blues musician |
| King, Martin Luther (12) | American clergyman, activist |
| King, Melanie (1) | |
| King, Stephen (108) | American author |
| Kingsley, Charles (1) | English author and historian |
| Kingsolver, Barbara (2) | American author |
| Kinison, Sam (1) | American comedian and actor |
| Kinsella, Sophie (2) | |
| Kipling, Joseph Rudyard (3) | English author and poet |
| Kissinger, Henry (2) | |
| Kl |
| Klein, Stephanie (1) | American blogger and author |
| Kleitman, Daniel (1) | American mathematician |
| Kleypas, Lisa (3) | American author |
| Kn |
| Knightley, Keira (2) | English actress |
| Knox, Jen (1) | American writer |
| Ko |
| Kodály, Zoltán (4) | Hungarian composer |
| Koestler, Arthur (4) | Hungarian author and journalist |
| Konecky, Edith (1) | American feminist novelist |
| Koontz, Dean (7) | |
| Kossuth, Lajos (5) | Hungarian statesman |
| Kosztolányi, Dezső (3) | Hungarian author, poet, translator, journalist |
| Kölcsey, Ferenc (1) | Hungarian poet |
| Kr |
| Krauss, Lawrence M. (2) | American physicist |
| Kroc, Ray (2) | American fast food businessman |
| Kronecker, Leopold (1) | German mathematician |
| Kronenberger, Louis (1) | |
| Ku |
| Kuban, Karla (1) | American author |
| Kundera, Milan (3) | Czech-French author, playwright and poet |
| Kurtz, Paul (1) | American skeptic and secular humanist |
| Kurzweil, Ray (6) | American inventor and author |
| Kusturica, Emir (2) | Serbian director, screenwriter, actor, producer, and musician |