Sienna Betts (born October 3, 2006) is an American basketball player who attends Grandview High School, where she is ranked as the No.

Betts was born in Vitoria-Gasteiz, Spain and moved around the country during her childhood due to the basketball career of her father, Andrew.

[11] In November 2023, she verbally committed to play college basketball at UCLA alongside her sister Lauren.

[12][13] On May 18, 2024, Betts was named to the United States under-18 national team for the 2024 FIBA Under-18 Women's AmeriCup.

During the final against Canada she recorded 15 points and nine rebounds to help the United States win a gold medal.