Authors Born on January 1
- Jona Weinhofen Guitarist, 1983
- Jonah Peretti Entrepreneur, 1974
- Jonas Armstrong Actor, 1981
- Jonathan Raymond Writer, 1953
- Julia Kent Cellist, 2000
- Kabir Poet, 1440
- Kamala Markandaya Novelist, 1924
- Karen Chance Novelist, 2000
- Karen Essex Novelist, 1900
- Karen Maitland Writer, 1956
- Kate Braverman Novelist, 1950
- Kate Crawford Academic, 2000
- Kate Klise Writer, 1963
- Katherine Philips Poet, 1631
- Kathleen Casey Politician, 1953
- Kathryn Hughes Academic, 1959
- Kaui Hart Hemmings Writer, 1975
- Kevin Wilson Writer, 1978
- Kim Hawthorne Actress, 2000
- Kim Philby Agent, 1912
- King Solomon King, 1011
- Klaus Lackner Professor, 2000
- Kresley Cole Novelist, 2000
- Kurt Johnstad Screenwriter, 2000
- L.A. Meyer Author, 1942
- L.A. Weatherly Writer, 1967
- Lael Brainard Economist, 1962
- Laird Barron Author, 1970
- Lakhdar Brahimi Diplomat, 1934
- Lance Secretan Motivational Speaker, 1939
- Lao Tzu Philosopher, 604
- Laura Anne Gilman Author, 1967
- Leonard Mlodinow Theoretical Physicist, 1954
- Liang Chow Artistic Gymnast, 1968
- Lucy Walker Film Director, 2000
- Ludovic Halevy Author, 1834
- Luis Alberto Urrea Poet, 1955
- Luke Davies Writer, 1962
- Lynn Good Businesswoman, 1953
- Mahavira Philosopher, 599