Authors Born on March 21
- Adrian Chiles Television Presenter, 1967
- Adrian Peterson American Football Player, 1985
- Albert Allen Bartlett Physicist, 1923
- Alda Merini Poet, 1931
- Alexandra Cousteau Film Maker, 1976
- Ali Abdullah Saleh Politician, 1947
- Allen Coulter Film Director, 1961
- Andre Laurendeau Journalist, 1912
- Angela Merici Religious Leader, 1474
- Anna Mickelson Athlete, 1980
- Antoine Griezmann Football Player, 1991
- Ayrton Senna Racecar Driver, 1960
- Benito Juarez Lawyer, 1806
- Boris Mironov Ice Hockey Player, 1972
- Brenda Shaughnessy Poet, 1970
- Brian Clough Football Player, 1935
- Carwyn Jones Politician, 1967
- Cenk Uygur Political Activist, 1970
- Charles Pratt, 1st Earl Camden Politician, 1714
- Chip Taylor Composer, 1940
- Dalian Atkinson Football Player, 1968
- David W. Blight Professor, 1949
- Dean Burk Biochemist, 1904
- Dee Hock Chief Executive Officer, 1929
- Denise Di Novi Film Producer, 1956
- Deryck Whibley Musician, 1980
- Donald Mason Singer, 1975
- Eddie Money Musician, 1949
- Edsel Dope Singer, 1974
- Edward Boches Professor, 1954
- Elizabeth Riddell Poet, 1910
- Eric Rohmer Film Director, 1920
- Eustace Percy, 1st Baron Percy of Newcastle Politician, 1887
- Extra P Rapper, 1972
- Fanny Lewald Author, 1811
- Fausto Cercignani Scholar, 1941
- Florenz Ziegfeld Producer, 1867
- Frankie Cosmos Musician, 1994
- Fred F. Fielding Lawyer, 1939
- Garry Tan Businessman, 1981