W.C. Fields famously advised against ever working with children or animals. While any discussion of thespian animals can wait for another day, I come in defense of child actors, many of whom have delivered outstanding performances in the movies.
One hopes the gifted young actors listed below weren’t subjected to the sort of head games that Jackie Cooper was subjected to on the set of 1931’s Skippy. Director Norman Taurog, irked that Cooper could not cry on cue, told the 8-year-old his dog would be shot unless he got the waterworks going.

Cooper became the first child nominated for an Academy Award, but it is unlikely he cared much for Taurog, who was also his uncle, after that production.
20. Jackie Coogan, The Kid (1921, dir. Charlie Chaplin)
19. Mary Badham, To Kill a Mockingbird (1962, dir. Robert Mulligan)
18. Jodie Foster, Taxi Driver (1976, dir. Martin Scorsese)
17. Elsie Fisher, Eighth Grade (2018, dir. Bo Burnham)
16. Frankie Corio, Aftersun (2022, dir. Charlotte Wells)
15. Ana Torrent, The Spirit of the Beehive (1973, dir. Victor Erice)
14. Quvenzhané Wallis, Beasts of the Southern Wild (2012, dir. Benh Zeitlin)
13. Brooklyn Prince, The Florida Project (2017, dir. Sean Baker)
12. Linda Manz, Days of Heaven (1978, dir. Terrence Malick)
11. Victoire Thivisol, Ponette (1996, dir. Jacques Doillon)
10. Jean-Pierre Léaud, The 400 Blows (1959, dir. François Truffaut)
9. Christian Bale, Empire of the Sun (1987, dir. Steven Spielberg)
8. David Bradley, Kes (1969, dir. Ken Loach)
7. Keisha Castle-Hughes, Whale Rider (2002, dir. Niki Caro)
6. Haley Joel Osment, The Sixth Sense (1999, dir. M. Night Shyamalan)
5. Ivana Baquero, Pan’s Labyrinth (2006, dir. Guillermo del Toro)
4. Jacob Tremblay, Room (2015, dir. Lenny Abrahamson)
3. Patty Duke, The Miracle Worker (1962, dir. Arthur Penn)
2. Tatum O’Neal, Paper Moon (1973, dir. Peter Bogdanovich)
1. David Bennent, The Tin Drum (1979, dir. Volker Schlöndorff)

Honorable mention: Jamie Bell in Billy Elliot (2000, dir. Stephen Daldry), Jackie Cooper in The Champ (1931, dir. King Vidor), Kirsten Dunst in Interview with the Vampire (1994, dir. Neil Jordan), Brigitte Fossey in Forbidden Games (1952, dir. René Clément), Jodie Foster in The Little Girl Who Lives Down the Lane (1976, dir. Nicolas Gessner), Alan Kim in Minari (2020, dir. Lee Isaac Chung), Margaret O’Brien in Meet Me in St. Louis (1944, dir. Vincente Minnelli), Anna Paquin in The Piano (1993, dir. Jane Campion), River Phoenix in Stand by Me (1986, dir. Rob Reiner), Natalie Portman in Léon: The Professional (1994, dir. Luc Besson), Millicent Simmonds in A Quiet Place (2018, dir. John Krasinski), Hailee Steinfeld in True Grit (2010, dir. Joel Coen), Henry Thomas in E.T. The Extra-Terrestrial (1982, dir. Steven Spielberg), Natalie Wood in Miracle on 34th Street (1947, dir. George Seaton), Yuya Yagira in Nobody Knows (2004, dir. Hirokazu Kore-eda)