Yui Aragaki is a Japanese idol, model, actress, singer, seiyū and occasional radio show host. She is most well-known for her role in the 2007 movie "Koizora" (also known as "Sky of Love") which was a box office hit.

Yui Aragaki was born in Naha, Okinawa Prefecture on June 11, 1988, and has two older sisters. After seeing an audition notice for the junior fashion magazine Nicola (ニコラ Nikora), she applied for it and won the Grand Prix award for the audition. In 2001, at the age of 13, she began her Nicola modelling career and was very well received as a Nicola model, having set a record for appearing on cover for 15 times. A fellow Nicola model Ayako Enomoto gave her the popular nickname "Gakki."