| Youngest Gabor | 14 |
| Youngest Gabor sister | 21 |
| Youngest Girl Scouts | 20 |
| Youngest goal scorer in MLS history | 35 |
| Youngest golfer ever to win a U.S.G.A. adult event (age 13) | 59 |
| Youngest golfer to shoot his age (67) in a P.G.A. Tour event | 60 |
| Youngest Greek god | 18 |
| Youngest group in the Girl Scouts | 33 |
| Youngest Hall-of-Famer (at age 22) to hit 100 home runs | 55 |
| Youngest heavyweight champion | 29 |
| Youngest inductee to the NHL Hall of Fame (31 years old) | 56 |
| Youngest Indy 500 driver | 24 |
| Youngest Ivy League school | 26 |
| Youngest Lincoln | 16 |
| Youngest major general in U.S. history | 38 |
| Youngest major leaguer in 1994 and 1995 | 39 |
| Youngest male tennis player to be No. 1 in the ATP Rankings | 59 |
| Youngest March girl | 19 |
| Youngest March sister | 21 |
| Youngest Marx | 13 |
| Youngest Marx brother | 21 |
| Youngest Masters champ | 22 |
| Youngest member of a 1990s girl group | 37 |
| Youngest member of a noted comedy troupe | 40 |
| Youngest member of Pooh's crowd | 35 |
| Youngest member of the 500-homer club | 37 |
| Youngest MLB player to hit 600 homers | 37 |
| Youngest Munster | 16 |
| Youngest NHL Hall of Fame inductee | 34 |
| Youngest NHL player to be inducted into the Hall of Fame | 56 |
| Youngest Obama | 14 |
| Youngest of a zany foursome | 27 |
| Youngest of Alcott's March sisters | 38 |
| Youngest of Chekhov's "Three Sisters" | 51 |
| Youngest of five famous brothers | 32 |
| Youngest of rock's Hanson brothers | 38 |
| Youngest of the Brady girls | 27 |
| Youngest of the Brontë sisters | 33 |
| Youngest of the Culkin brothers | 31 |
| Youngest of the Gabor sisters | 29 |
| Youngest of the Gabors | 22 |
| Youngest of the gods | 20 |
| Youngest of the Greek gods | 26 |
| Youngest of the Jetsons | 23 |
| Youngest of the March sisters | 29 |
| Youngest of the Marx Brothers | 29 |
| Youngest of the musical Jacksons | 32 |
| Youngest of the three Prozorov sisters | 38 |
| Youngest Olympian | 17 |
| Youngest one in "My Three Sons" | 41 |
| Youngest Oscar winner | 21 |
| Youngest Oscar winner in history | 32 |
| Youngest person to have won an Oscar, Emmy, Tony, and Grammy | 60 |
| Youngest person to hit a home run in a World Series | 51 |
| Youngest person to win a Grammy | 31 |
| Youngest person to win the Nobel Peace Prize | 44 |
| Youngest player in Curtis Cup history | 37 |
| Youngest player in history to reach 450 HRs | 43 |
| Youngest player inducted into the NHL Hall of Fame | 50 |
| Youngest player to be inducted in the Hockey Hall of Fame | 57 |
| Youngest player to be inducted into the Hockey Hall of Fame | 59 |
| Youngest player to hit 500 HRs, familiarly | 42 |
| Youngest player to join the 500 home run club, familiarly | 57 |
| Youngest player to join the 500 HR club | 39 |
| Youngest player to join the 500-homer club | 42 |
| Youngest player to join the 500-HR club | 39 |
| Youngest player to play in a PGA tour event | 43 |
| Youngest player to qualify for an L.P.G.A. Tour event | 53 |
| Youngest player to win a major-league batting title (1955) | 58 |
| Youngest possible voter | 23 |
| Youngest QB to win a Super Bowl, at age 24 | 42 |
| Youngest Simpson | 16 |
| Youngest sister in "Little Women" | 43 |
| Youngest son | 12 |
| Youngest son of Arthur and Molly Weasley | 40 |
| Youngest son of William the Conqueror | 37 |
| Youngest sons | 13 |
| Youngest to reach 500 HRs | 25 |
| Youngest von Trapp, in film | 27 |
| Youngest White House resident since Caroline | 44 |
| Youngest Wilcox child in "Howards End" | 48 |
| Youngest winner in "American Idol" history | 52 |
| Youngest winner of the Album of the Year Grammy | 47 |
| Youngest winner of the Best Actor Oscar | 39 |
| Youngest world chess champion before Kasparov | 45 |
| Youngest-ever French Open champion | 34 |
| Youngest-ever French Open winner | 32 |
| Youngest-ever French Open winner Michael ___ | 44 |
| Youngest-ever French Open winner, 1990 | 38 |
| Youngest-ever Oscar winner | 26 |
| Youngish ones | 13 |
| Youngman | 8 |
| Youngman forte | 14 |
| Youngman from Liverpool | 23 |
| Youngman gag | 12 |
| Youngman of one-liners | 22 |
| Youngman offered his | 20 |
| Youngman offering | 17 |
| Youngman or Berle, e.g. | 23 |
| Youngman quip | 13 |