Eya Guezguez, a sailor from Tunisia, died in a training accident on Sunday.
At the Tokyo Olympics, Guezguez competed in the women's 49er FX category with her twin sister Sarra, who was two minutes older.
The Tunisia Olympic Committee described her death as a tragedy in the sports scene, while the Minister of Sports and Youth paid tribute to her.
Debutants Eya and Sarra finished in the bottom of their event in Tokyo.
"I am shocked by the news of sailor Eya Guezguez's death," International Olympic Committee president Thomas Bach said.
She was an inspiring talent and role model for her athletes.
Eya Guezguez and her twin sister Sarra will continue to inspire girls everywhere. Our thoughts are with her family, friends and the Olympic community in Tunisia.
The CNOT's Facebook page said that rising star Guezguez died while training.
A boat carrying the sisters and their coach capsized in windy weather, with the CNOT president telling local radio that the coach was in a speedboat at the time.
The coach was able to help Sarra flee the rigging before locating Eya, but he was unable to save her.
The young Olympian died after being taken to the hospital.
Some reports say the accident was caused by bad weather and strong winds.
Tunisia's sporting community has been shocked and angered by the incident, with many questioning management and the nature of safety equipment.
Muslims were due to break their fast a few hours before the incident occurred.
May God have mercy on the deceased, grant her eternal rest in paradise, and grant her family and relatives a beautiful patience and solace, according to a statement from CNOT.