Lorde, whose real name is Ella Yelich-O'Connor, made the No.1 spot on the list of 16 teenagers from around the world, followed by Ko in second place.
Lorde, 17, rocketed to international fame this year with the release of her single Royals, followed up the release of her album Pure Heroine.
Time magazine said the proof of Lorde's success came when New York City Mayor-elect Bill de Blasio won the election and walked on stage to Lorde's defiant Royals.
Signed by a label at age 13, Lorde surpassed Miley Cyrus in September for the top spot on iTunes with the song.
Time said Lorde was "forging her own path", turning down an opportunity to join Katy Perry on tour because it "didn't feel right" at the time.
Meanwhile 16-year-old Ko has multiple LPGA wins, turning pro this year after the LPGA waived the age requirement for her to join.
She is already fifth in the women's world rankings after just 23 tournaments and is the youngest person ever to win a professional golf tour event including an LPGA.
The list of 16 teenagers includes Malala Yousafzai, the 16-year-old Pakistani activist who was shot in the head for promoting girls' education under Taliban rule; American singer Justin Bieber, 19, and Malia Obama, 15, the daughter of United States President Barack Obama.
- Natalie Akoorie of the New Zealand Herald
