Olesya Rulin, born Olesya Yurivna Rulina on March 17, 1986, in Moscow, Russian SFSR, Soviet Union, is a Russian-American actress best known for her role as Kelsi Nielsen in the High School Musical franchise.

She spent her early childhood in Likhoslavl before moving to the United States at the age of eight to join her father, who had emigrated two years earlier. They first lived in Texas before settling in Utah, where she graduated from West Jordan High School in 2005.

Olesya Rulin is also a trained ballet dancer and can play the piano, skills that have complemented her acting career.

Before pursuing acting full-time, she worked as a certified nursing assistant and at stores such as Victoria's Secret and Nordstrom. Her acting career took off when she was cast in Disney Channel's Hounded at the age of 12.

She went on to star in several Disney Channel Original Movies, including Halloweentown High, The Poof Point, and Hounded. Her breakout role came with the High School Musical series, where she reprised her role as Kelsi Nielsen in all three films, performing several memorable musical numbers.

Olesya Rulin has appeared in numerous feature films, including Private Valentine: Blonde & Dangerous (2008), Flying By (2009), Expecting Mary (2010), and Family Weekend (2013).

She also played the lead in the psychological drama Apart (2011) and had a recurring role in the ABC series Greek. In 2015, she joined the cast of the PlayStation Network series Powers, playing the role of Callista Secor for two seasons.

Her personal life is marked by her passion for environmentalism and sustainability. Growing up in a small village in the USSR, she developed a deep appreciation for nature and the importance of mindful consumption.

She and her mother co-own 460 acres of land in Russia that has been turned into a nature reserve. She is also a pescetarian, focusing on a diet that is both healthy and environmentally friendly. She married entrepreneur Joseph Noel Pauline on November 11, 2021, and they welcomed their first child in 2023.