Greta Thunberg (20 years old)
Jan 3 Swedish climate change activist, born in Stockholm, Sweden
- Jan 4 Jaeden Martell, American actor (Bill Denbrough-It; Knives Out), born in Philadelphia, Pennsylvania,
- Jan 24 Johnny Orlando, Canadian pop singer-songwriter ("Waste My Time"), born in Mississauga, Ontario
- Jan 26 Robby Novak [Kid President], American internet personality (YouTube), born in Henderson, Tennessee
- Feb 20 Atthaya Thitikul, Thai golfer (youngest female winner in pro event), born in Ratchaburi, Thailand
Olivia Rodrigo (20 years old)
Feb 20 American actress and singer-songwriter ("Driver's License"), born in Temecula, California
- Mar 6 Millicent Simmonds, American deaf actress (A Quiet Place), born in Bountiful, Utah
- Mar 9 Sunisa Lee, American gymnast (All-round Olympic Gold 2021), born in St. Paul, Minnesota
- Mar 26 Bhad Bhabie [Danielle Bregoli], American rapper (These Heaux), born in Boynton Beach, Florida
- Apr 3 Elsie Fisher, American actress (Eighth Grade), born in Riverside, California
- Apr 29 Barbaro, American thoroughbred racehorse (d. 2007)
- Apr 29 Maud Behn, Princess of Norway
- May 5 Carlos Alcaraz, Spanish tennis player (US Open 2022), born in Villena, Spain
- May 12 Madeleine McCann, English child who mysteriously disappeared on holiday in Spain in 2007, born in Leicester, England
- May 19 JoJo Siwa, American dancer, singer and YouTube personality, born in Omaha, Nebraska
- Jun 16 Anna Cathcart, Canadian actress (Odd Squad; To All the Boys I've Loved Before), born in Vancouver, British Columbia
- Jul 1 Storm Reid, American actress (A Wrinkle in Time, Euphoria), born in Atlanta, Georgia
- Jul 1 Tate McRae, Canadian singer-songwriter and dancer (You Broke Me First), born in Calgary, Alberta
- Jul 4 Alessia di Matteo, Italian medical figure (1st person to survive the transplantion of eight organs in a single operation), born in Genoa, Italy (d. 2005)
- Aug 17 The Kid Laroi [Charlton Howard], Australian singer-songwriter (Without You), born in Waterloo, Australia
- Aug 18 Max Charles, American actor (The Amazing Spider-Man; The Neighbors), born in Dayton, Ohio
- Aug 20 Prince Gabriel of Belgium, second child of King Philippe and Queen Mathilde of Belgium, born in Erasmus Hospital, Anderlecht, Brussels, Belgium
- Aug 24 Alexandre Coste, Son of Albert II, Prince of Monaco, born in Paris
- Sep 3 Eileen Gu, Chinese freestyle skier (Olympic gold halfpipe, big air 2022; World C'ship gold halfpipe, slopestyle 2021), born in San Francisco, California
- Sep 30 Bella Ramsey, English actress (Games of Thrones, The Last of Us), born in Nottingham, England
- Nov 8 Lady Louise Windsor, British royal, born in Surrey, England
- Dec 1 Robert Irwin, Australian TV personality and photographer, born in Buderim, Australia
- Dec 7 Princess Catharina-Amalia of the Netherlands, eldest child of King Willem-Alexander and Queen Máxima, born in HMC Bronovo, The Hague, Netherlands
About 2003
How Old? 19 or 20 years old
Generation: Generation Z
Chinese Zodiac: Horse (Feb 12, 2002 - Jan 31, 2003),
Goat/Sheep (Feb 1, 2003 - Jan 21, 2004)