Cydonie Camille Mothersille (born 19 March 1978) is a female former track and field sprinter from the Cayman Islands.

Her greatest achievements were in the 200 m, including a bronze at the 2001 World Championships in Athletics, Commonwealth gold in 2010 and a silver at the 2003 Pan American Games.

While in high school, she was discovered by her high school's physical education teacher Evelyn Rockette and began her track career.

In 1996, she was awarded the Austin Sealy Trophy for the most outstanding athlete of the 1996 CARIFTA Games.

In 2011, Cydonie was the highest paid athlete from the Cayman Islands (male or female) making $85,000 (USD).