Everyone knows that teenagers on television are very rarely played by teens IRL — but in some cases, the actors aren't that much older than their characters. In some very rare cases, young actors on TV get to play their own age. The list below consists of TV Time users' favorite actors under the age of 30. The oldest began playing teens when they were barely in their twenties (like Pretty Little Liars' Lucy Hale and Ashley Benson), while the youngest on the list plays a precocious science genius (Young Sheldon's Iain Armitage).
And one person on the list has been on TV for over a decade now and is still playing teens — which is fine, since she's still a teenager herself, believe it or not (Chilling Adventures of Sabrina's Kiernan Shipka).
25. Alisha Boe, 21
The 13 Reasons Why star was born in Norway and moved to Los Angeles as a kid, and is only a couple of years older than her character.
24. K.J. Apa, 21
The Kiwi actor is now of legal drinking age in the U.S., but was still a teenager when he was cast as the all-American Archie Andrews on The CW's Riverdale.
23. Cameron Monaghan, 25
The actor also known as Ian Gallagher on Showtime's Shameless was actually still in high school when he began playing the Chicago family's second-oldest son.
22. Lucy Hale, 29
Thankfully, though she played a secret-keeping teenager on Pretty Little Liars for seven seasons, Hale has aged out of high school roles.
21. Adelaide Kane, 28
Mary, Queen of Scots was 16 when she was married off to the Dauphin of France, and widowed just two years later. Australian actress Kane was 23 when she began playing the monarch on The CW's historical drama Reign.
20. Ashley Benson, 28
Hale's PLL costar was the second-youngest of the main PLL characters when she was cast as Pennsylvania teen Hanna Marin.
19. Brandon Flynn, 25
Flynn plays Boe's 13 Reasons Why on-screen love, Liberty High School jock Justin. He made headlines in 2017 for his romance with singer Sam Smith (though the two have since split).
18. Emily Bett Rickards, 27
The first character on this list who wasn't a teen when we met her is Felicity Smoak, who was originally just a one-off tech expert helping out Arrow hero Oliver Queen but (spoiler alert!) eventually married him.
17. Debby Ryan, 25
The former Disney Channel star plays teen beauty queen on Netflix's Insatiable, which was just renewed for a second season.
16. Keir Gilcrist, 26
Gilcrist played Toni Collette's teenage son on United States of Tara when he was an actual teen, but now stars as an 18-year-old with autism on Netflix's Atypical.
15. Camila Mendes, 24
Mendes had just graduated from NYU when she was cast as archetypal brunette beauty Veronica on The CW's Riverdale.
14. Iain Armitage, 10
Armitage doesn't play a teen on TV — he just goes to school with them as super-smart 9-year-old Sheldon Cooper on CBS' Big Bang Theory prequel Young Sheldon.
13. Úrsula Corberó, 29
Corberó plays runaway bank robber Tokyo, who was recruited by the Professor to join his heist in the Spanish-language series La casa de papel, a.k.a. Money Heist.
12. Kiernan Shipka, 19
Sabrina Spellman's witchy powers kick in when she turns 16 on Chilling Adventures of Sabrina. And it's hard to believe that though we've seen Shipka on TV for more than a decade beginning with Mad Men, she's still not even 20.
11. Jessica Barden, 26
Barden wowed audiences as teenage runaway Alyssa in The End of the F***ing World.
10. Dylan O'Brien, 27
O'Brien was just out of his teens when he was cast as the BFF of the titular werewolf on MTV's remake of the 1985 movie Teen Wolf.
9. Alex Lawther, 23
Netflix has ordered a second season of The End of the F***ing World, which follows Lawther as 17-year-old James, who thinks he's a psychopath and tries to kill his classmate Alyssa (but runs away with her instead).
8. Eliza Taylor, 29
Saving humanity on a post-apocalyptic Earth is a hard job, especially when you're tasked with doing it when you're still a teenager like Clarke on The 100.
7. Dylan Minnette, 21
The actor was just a teen himself when he began playing Clay on 13 Reasons Why, a lovestruck teen mourning the death of his classmate.
6. Madelaine Petsch, 24
The Washington-born actress plays Riverdale Queen Bee Cheryl Blossom.
5. Lili Reinhart, 22
Like her Riverdale costar Apa, Reinhart, who plays blonde beauty Betty Cooper, was still a teen when she started on the hit series.
4. Grant Gustin, 28
Luckily, Gustin's on-screen alter-ego Barry Allen (a.k.a. The Flash) is the same age as the actor — and he's another character on this list who isn't a teenager (He did play teen singer "Sebastian" on Glee for several seasons when he was a young twentysomething IRL, however).
3. Elizabeth Gillies, 25
The Dynasty reboot's HBIC is another character who isn't actually a teenager, but Fallon Carrington is a young, smart, and powerful woman. Gillies got her start as a teen playing a teen on Victorious alongside Ariana Grande.
2. Freddie Highmore, 26
Highmore leads his second series (after A&E's Bates Motel) as the titular character on ABC's The Good Doctor, playing a medical resident on the autism spectrum.
1. Cole Sprouse, 26
The brooding loner from Riverdale got his start as a kid actor in movies and on the Disney Channel, but by the time he started on The CW high school drama he was already out of his teens.
